UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 1060 



ContrlbntiOD from the Forest Service 
WnXIAM B. GREELEY, Forester 



Washington, D. C. 



May, 1922 



SITKA SPRUCE 

ITS USES, GROWTH, AND MANAGEMENT 



By 
N. LEROY CARY, Forest Examiner 



CONTENTS 



Page 

Inttodactlon 1 

Geographic Distribution and Altitudinal 

Range 2 

Present Supply and Annual Cut 4 

Characteristics of the Wood 5 

Uses 6 

Logging and Milling H 

Size, Age, and Distinguishing Character- 

istica 10 

Occurrence 12 

Bottom-land Type 12 



Page 

Slope Type IS 

Composition and Volume of Stand ... 13 

Climatic and Soil Requirements 15 

Light Requirements 16 

Reproduction , j . 16 

Causes of Injury 18 

Growth 23 

yield 27 

Management 28 

Appendix 33 




WASHINGTON 
GOVERNMENT PBINTING OFFICE 

1922 



Vt- 



LIBRARY 0FC0NGKES8 

RECEIVED 

JUN 261922 

POCUMENTS WiVi4IOf> 



.577C3 



ul. 1060. U. S. Dept. of Agricuitu 



FRONTISPIECE. 




Two Magnificent Specimens of Spruce in Alaska. 



UNITED STATES DEPARTMENT OF AGRICULTURE 




,r, BULLETIN No. 1060 mm}W 



Contribution from the Forest Servi< 
WILLIAM B. GREELEY, Foreste 



Washington, D. C. 



May, 1922 



SITKA SPRUCE: ITS USES, GROWTH, AND 
MANAGEMENT. 

0_U ^ ' ^ By N. Lkkoy Caky, Forext Examiner. 



Page. 

Introduction 1 

Cieographic distribution and altitudl- 

nal range 2 

Present supply and annual cut 4 

Characteristics of the wood o 

Uses 6 

Logging and milling 8 

Size, age, and distinguishing charac 

teristics 10 

Occurrence 1- 

Bottom-land type 1- 



Page. 

Slop,- type 13 

Composition and rolume of stand 13 

Climatic and soil requirements 15 

Light requirements ItJ 

Reproduction 16 

I'auses of injury 18 

Growth 23 

Yield 27 

Management 28 

Appendix 33 



INTRODUCTION. 

Sitka spruce {Picea sitch&nsis (Bong.) Trautv. and Mayer), also 
called tideland spitice, is an important timber tree of the Pacific coast 
i-egion. growing naturally from Alaska to northern California. It 
is found largely at low altitudes and never very far from the ocean. 
In Alaska it is the principal tree of commerce ; in (Oregon and Wash- 
ington it is one of the components of the dense and luxuriant conifer- 
ous forest that blankets the humid strip of country on the west side 
of the coastal ranges. Here several of its associate trees are more 
abundant than Sitka spruce; but in the superior qualities of its wood, 
in its magnificent form, and in its immense size it has no superior 
excejit the redwood with which it mixes at the south end of its range. 

Because Sitka spruce does not ordinarily occur in pure stands, 
■it must be logged in conjimction with otlier timber species — with 
Douglas fir, western hemlock, and western red cedar in Washington 
and Oregon, and with the western hemlock in Alaska. The greater 
part of the virgin forests in which Sitka spruce occurs has not been 

Note. — The writer wishes to acknowledge the valuable assistance given him by Messrs. 
H. T. Glsborne, R. H. Weidman, and others in the preparation of this manuscript. 
85569—22 1 



2 BULLETIN 1060, U. S. DEPARTMENT OF AGKICULTUKE. 

reached by lumbering operations ; hence until recently the cut of this 
timber had been relatively small. It was not well known in the 
world or national markets until an extraordinary demand for it 
arose during the war because its wood was found to be superior for 
aii'plane construction. Within the space of a few months in 1917 
this species, which had been of decidedly secondary importance in 
the lumber industry, became one of the woods most eagerly sought. 
To effect an enormous increase in the production of Sitka spruce 
and to obtain lumber of the quality needed for airijlane wing beams, 
a special organization of the War Department — the Spruce Pro- 
duction Division — was created. The great activity of this organiza- 
tion in promoting the lumbering of this needed Sitka spruce air- 
plane stock in conjunction with the local lumber industry is one of 
the interesting chapters in the history of the war industries.^ 

Although Sitka spruce may never again be so eagerly sought and 
so extensively cut as during the war, it has so many superior quali- 
ties in the estimation of foresters and lumbermen that it will always 
play an important role in the forest management of the Pacific 
coast region. It has a habit of rapid growth, makes a large yield 
per acre, lends itself fairly well to forest management, and produces 
a wood which has large value for many special purposes, prominent 
among which is the manufacture of paper. 

GEOGRAPHIC DISTRIBUTION AND ALTITUDINAL RANGE. 

The botanical range of Sitka spruce, as shown in figure 1, lies 
along the north Pacific coast, roughly between 40° and 60° of lati- 
tude, and in that narrow strip of shore line often described as the 
fog belt. Its width is nowhere more than 200 miles from the coast 
line eastward, and usually much less. 

In Alaska this species occurs as far north as the west shore of 
Cook Inlet, the north end of Kodiak Island, and along the Lynn 
Canal, and is generally abundant southward, on the islands and 
mainland near the coast of southeastern Alaska. In British Colum- 
bia it is found chiefly along the shore line and on the lowlands of 
the large rivers like the Fraser. 

In the United States it is found in the western part of the State 
of Washington on the lower benches and bottomlands of the rivers 
along the Pacific coast, and less commonly about Puget Sound, oc- 
curring sporadically in the foothills of the Cascade Range. In. 
Oregon it is found under similar conditions but almost exclusively 
west of the crest of the Coast Range; it extends up the Columbia 
River only 50 miles from its mouth, and farther south not more than 

' " History of Spruce Production Division, United States Army," issued by the United 
states Spruce Production Corporation. 



SITKA spruce: uses, growth, management. 



20 miles inland. In California it jjrows close to the shore line and 
along the Smith and Klamath Rivers; the southern limit of its 
range is near Casper, in Mendocino County. 




Fig. 1. — Botanical distribution of Sitka spruce, sliown by sliaded areas. 

Heavy commercial stands of this species are found all the way 
from southeastern Alaska to Coos Bay, Oreg., though by no means 
does this tree preponderate in the forest growth throughout this strip 
nor is it even present everywhere. The heaviest stands of Sitka 
spruce, in its entire range, occur in the northwestern part of the 



4 BULLETIN 1060, V. S. DEPARTMENT OF AGRK^ULTURE. 

Olympic Peninsula (Washington) along the Solecliick. Dickey, and 
Hoko Rivers at elevations between 400 and 600 feet. 

The upper altitudinal limit has been noted by many observers as 
being higher in the northern part of its range than farther south; 
it is seldom, however, more than 3,000 feet above sea level. In the 
States it is doubtful whether it grows at that elevation; actually 
it has been found at 2.500 feet on the west side of the Olympic 
Mountains, at 2,100 feet near Bandera in the Cascade Range of 
Washington, and at about 2,100 feet on the slopes of Saddle Moun- 
tain in Clatsop County, Oreg. (PI. I.) Although botanically it 
does occur afthese elevations, an altitude of about 1,200 feet marks 
the upper limit of its growth in commercial quantities. The lower 
limit extends to the very surf line of the Pacific. 

PRESENT SUPPLY AND ANNUAL CUT. 

The total .stand of Sitka spruce in America is estimated at 40 
to 44 billion feet. As shown in Table 1, more than one-third 
occurs in Alaska, one-third in British Columbia, and the remainder 
in Washington, Oregon, and California. 

It is estimated that about 1,600 million board feet of the most ac- 
cessible spruce has been cut since the estimates given in Table 1 were 
made.^ An additional billion board feet is estimated to have blown 
down by the catastrophic wind storm of January, 1921, which oc- 
curred in the heart of the Sitka spruce belt of Washington. 

T.\RLE 1. — E.ttinuited stand of Sitka spruce in 1918.' 

State : Million fiet b. m. 

Washington 6, .57.5 

Oregon 4,374 

California 187 

Sitka si^ruce forms only 1.5 per cent by volume of the total mer- 
chantable stand of timber west of the Cascades in Oregon and Wash- 
ington. In British Columbia it comprises 6.7 per cent of the timber 
along the coast. Of the coastal forests of southeastern Alaska it 
forms about 20 per cent. Approximately 50 per cent of the entire 
stand of Sitka spruce is in private ownership. Detailed estimates 
of ownership appear in Table 10. 

The cut of spruce in Washington and Oregon increased over 50 
per cent in the year 1918, and practically all of this increase was 
made \\y> of Sitka spruce. The cut of spruce in the United States 
increased very little, and in general is declining. For a number of 

^ " Supplies and Production of Aircraft Woods," by W. N. Sparhawk. National Adylsory 
Committee tor Aeronautics, Fifth Annual Report. Ept. 67, p. 9, 1919. 

" Figures for all localities except Britlsb Columbia compUed by Forest Service from 
county records and private, State, and Government estimates. British Columbia figures 
from " Forests of British Columbia," by H. N. Whitford and R. D. Craig, p. 330, 1918. 



State : Million feet b. m. 

Alaska 15,000 to 18,000 

British CoHiml)ia 1.5,186 



SITKA SPRUCE : USES, GROWTH, MANAGEMENT. 5 

yeai's Maine had been the leadinfr spruce-producing State, cutting 
chiefly red spruce; but the pressing need for spruce aircraft lumber 
for war uses stimulated iDroduction in the Pacific Northwest to such 
an extent that in 1918 Washington took first place in the produc- 
tion of spruce with a cut of over 275,000,000 board feet, Oregon 
second with a cut of over 215,000,000, while Maine dropped to third 
place. As is shown in detail in Table 2, the cut of spruce for 1918 
compri.sed 6 and S per cent, respectively, of the total limiber pro- 
duction in Washington and Oregon, less than 2 per cent in Cali- 
fornia, and practically the entire cut in Alaska. No distinction is 
made between species of spruce, but Sitka spruce probably forms over 
95 per cent in these three Statas. In British Columbia the ratio was 
about the same as in Washington. The total cut of Sitka spruce in 
1918, exclusive of British Columbia, exceeded 536.000,000 board feet. 

Table 2. — Total reported cut of spruce lumber, 1915-1918. 

[No distinction is made between species of spruce: Sitka spruce probably forms over 95 per cent in Wash- 
ington, Oregon, and California.] 





Nimiber 


Quantity 


Per cent 


Per cent 
of total 


Average 
valueper 
1,000 feet 
f. 0. b. 
miU. 


Year. 


of active 


of spruce 


of total 


spruce 


mills re- 


reported 


lumber 


cut in 




porting. 


cut. 


cut. 


United 
States. 






Mfeet. 








Wasliington: 




b.m. 








19151 


49 


196,203 


5.3 


16.4 


tl4. 08 


1916 2 


65 


221,295 


5.0 


19.6 




1917 3 


66 


198,271 


4.6 


20.3 


22.34 


1918 < 


60 


275,826 


6.0 


28.1 


23.81 


Oregon; 












1915 > 


20 


65,327 


4.3 


5.5 




1916 > 


23 


96,245 


4.3 


8.5 


11.96 


1917' 


26 


120,647 


4.9 


12.3 


28.28 


1918 < 


35 


215,828 


8.0 


22.0 


27.03 


California: 
















9,477 
13,871 


0.8 
0.9 






19161 


2 


1.2 


14.44 


. 1917 » 


4 


20,659 


1.5 


2.1 


17.50 


1918 < 


g 


16,663 


1.3 


1.7 


20.75 




18 


28, 716 


98.0 




23.00 


British Columbia: 
















'56,360 
'49,077 






13.60 




48 


5.6 




14.66 









1 "Production of Limjber, Lath, and Shingles in 1916 and Lumber in 1914," TJ. 8. Dept. Agr. Bui. 606, 

p. 20. 

'" Production of Lumber, Lath, and Shingles in 1916," U. S. Dept. Agr. Bui. 673, p. 21. 

' "Production of Lumber, Lath, and Shingles in 1917," U. S. Dept. Agr. Bui. 768, p. 21. 

'"Production of Lumber, Lath, and Shingles in 1918," U. S. Dept. Agr. Bui. 845, p. 24. 

i "Character and Distribution of the 1918 Lumber and Shingle Cut of Washington, Oregon, and Alaska, 
by Producing and Consuming Regions," by T. J. Starker, West Coast Lumberman, Vol. 36, No. 423, p. 26, 
1919. 

« " Forests of BritLsh Columbia." by H. N. Whitford and R. D. Craig, p. 178, 1918. 

' No distinction is made between species of spruce; probably about SO per cent Sitka spruce. 

CHARACTERISTICS OF THE WOOD. 

Sitka spruce wood is light, soft, straight-grained, tough, easily 
worked, and very strong for its weight. It is tasteless and contains 
very few resin ducts. The color of the heartw'ood is a pale pinkish 
brown, which blends imperceptibly into the creamy white of the 



6 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

sapwood. The longitudinal surface of tlie wood shows a silky sheen, 
and the tangential surface, less noticeably, slight indentations or 
dimples. There is no distinct line of demarkation between the sjjring- 
wood and the summerwood as in Douglas fir. 

Compai-ed with other woods of similar weight, Sitka spruce is of 
greater strength and toughness. Table 17 (Aj^pendix) shows the 
value of its mechanical properties as measured by laboratory tests. 
Individual test specimens may show a variation of as much as 16 per 
cent from the data on bending, compression, shearing, tension, and 
such propei'ties. 

Spiral grain is found in Sitka spruce as in other species, though not 
to any great extent. During the war specifications for airplane stock 
required that no spiral-grained wood be accepted which had more 
than 1 inch departure in 20 inches of length. Tests showed that a 
greater amount of twist caused a marked reduction in strength for 
aircraft purposes. Spiral grain in Sitka spruce can generally be 
detected in the standing tree by a twisting of the fluted portions of 
the lower trunk. 

The calorific power of one cord of air-dried Sitka spruce wood is 
52 per cent of that of a short ton of coal, and that of western hemlock 
and Douglas fir is 58 and 68 per cent, resjjectively. 

USES. 

The varied properties of Sitka spi-uce fit it for a wide variety of 
uses. It is the premier wood for the manufacture of aircraft. It is 
unsurpassed for pulp and is especially adapted for musical instru- 
ments. It is also a desirable wood for boxes, crates, barrels, veneer, 
and woodenware. 

By far the most extensive use to which the wood is put is the manu- 
facture of lumber. As such, in one form or another, it is used for 
about the same pur^DOses as the other spruces. About 40 per cent is 
used for construction and similar i^urposes without further manufac- 
ture. While not suitable for heavy construction, it is well adapted for 
many building uses in which light weight, ease in working, and 
ability to take and hold nails and paints are essential. It is especially 
suitable for large doors, such as are used for garages, freight houses, 
and similar structures. It is extensively used for beveled siding. As 
a car stock it is unsurpassed. The bulk of the lumber, however, is 
remanufactured into a large variety of products. 

More than half the lumber cut of this species is consumed by the 
planing mill, box, and crate industries. It cuts to advantage for 
doors, window and door frames, and molding. Belonging to the 
class of tasteless woods, Sitka spruce is extensively used for contain- 
ers in which articles of food are packed or handled. 



SLTKA SPRX^Ce: USES, GEOWTH, MANAGEMENT. 7 

Because of its light weight, combined with strength and tough- 
ness, Sitka spruce is the most desirable and most generally used wood 
for such airplane j^arts as wing beams, struts, longerons, ribs, and 
plywood parts. Although red, white, and Sitka spruce do not differ 
greatly in strength properties, the last species, on account of its 
greater size and consequently its greater proportion of clear lumber, 
is a more important source of aircraft material than the other two. 
Because of this and the relatively large supplies of virgin timber still 
remaining, Sitka spruce will probably for many years be a very im- 
portant species in the aircraft industry, notwithstanding the fact 
that the supply is far from the centers of manufacture. 

Because of the resonant quality of the wood, its even structure, the 
absence of vessels, the extremely fine and regularly distributed medul- 
lary rays, and the straight and long fibers, spruce generally is con- 
sidered to be the best wood for piano sounding-boards, as well as for 
musical instruments generally. Sitka spruce yields a large propor- 
tion of clear lumber and wood of selected quality for this purpose, 
but its rapid growth tends to lessen the resonant quality in compari- 
son with the slower growing eastern species. 

The wood is not durable in contact with the soil or when exposed to 
weather. It is less suitable for piling in salt water than are other 
species, because of its greater susceptibility to the ravages of the 
teredo, which may destroy it in one or two years. 

For the manufacture of white paper pulp by either the mechanical 
or the chemical process, spruce is the leading wood used. It is soft, 
white, and nonresinous, and its fibers are longer, more flexible, and 
stronger than those of most woods. Containing a maximum percent- 
age of cellulose, it gives a high yield by the chemical process. Al- 
though there are several species of spruce, no marked difference is 
noted in the pulps manufactured from them. A comparison of the 
character and uses of the pulp made from Sitka spruce with that 
made from white spruce, a wood that can be considered standard for 
pulping by the sulphite, sulphate, and mechanical processes, indicates 
no practical difference. 

Because of the long distance to the large paper markets of the East, 
the utilization of Sitka spruce for paper manufacture is relatively 
small. Of the domestic spruce consumption in the United States in 
1918 for the manufacture of paper, 35,385 cords, or 1.6. per cent, was 
Sitka spruce from the forests of Washington and Oregon. British 
Columbia utilizes about half as much Sitka spruce for this purpose 
as do the States of Oregon and Washington. Other species, includ- 
ing western hemlock, white fir, cottonwood, and Douglas fir, are util- 
ized on the Pacific coast in the manufacture of pulp, but Sitka spruce 
represents about 15 per cent of the total. 



8 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

The pulp, paper, and board industry of the West, a long-established 
one, is confined practically to the Pacific coast, with the pulp mills 
largely confined to the States of Oregon, Washington, and the 
province of British Columbia. Alaska has one pulp mill, established 
in 1921. There is every indication that this industry will grow 
rapidly in the next few years, with an abundant supply of pulp- 
wood, waterpower, and coal, taken in connection with the fact that 
the pulp-wood supply in the East is approaching depletion. 

LOGGING AND MILLING. 

The occurrence of Sitka spruce on the lowlands near tidewater, 
and along navigable or drivable rivers, on the benches and gently 
rolling country of the lower foothills makes logging relatively easy, 
and a mild climate permits j'ear-long operation. As the species 
occurs largely in association with Douglas fir, hemlock, and cedar, 
the method of logging is identical with that universally used in the 
heavy forests of the Pacific coastal region. Here large operations, 
powerful steam machinei*y, and heavy capital investments are the 
distinctive features of logging operations. (PL II.) These are 
required by the large size of the timber, the ground conditions, and 
the enterprise of the industry. 

Trees 6, 8, or 10 feet in diameter, standing on rough steep ground, 
are felled and converted into logs in such a way that the minimum 
of waste results; and logs, some of them scaling 10,000 feet and 
weighing 30 tons, are dragged with great dispatch over the ground 
or swung down steep slopes and over deep canyons on overhead 
cables. The greater part of the timber is transported from the woods 
to the mills or waterside over standard-gauge logging railroads for 
distances ranging from a few miles to 30 or more. (Pi. III.) To a 
limited extent motor trucks (PI. IV) are used in conveying logs, and 
in some cases in the Grays Harbor and Willapa Harbor regions of 
Washington logs are transported by driving streams. A large per- 
centage of the cut of Sitka spruce reaches the waterside along the 
Columbia River and in Puget Sound, Grays Hai-bor, and Willapa 
Harbor, where the logs are made into rafts and towed to the mills. 

Logging with animals in Oregon and Washington is confined to 
small operations getting out ties, shingle bolts, piles, and poles. 
In Alaska, operations are found only along the shore line, and there 
both hand and machine methods are employed. If the latter method 
is used the donkey engine is mounted on a float, the hauling line is 
led inshore a thousand feet or more, and the logs are skidded directly 
to the water to be towed to the mills. 

The sudden and urgent demand in 1917 for high-grade spruce 
timber for air^ilane material, which existing logging operations were 



Bui. 1060, U. S. Dept. of Agriculture. 




Group of Sitka Spruces in Clatsop County, Greg. 



BuL 106". U S Dept nf Aanrijlti] 




ul. 1060. U. S. Dept. of Agr 




Bui. 1050, U. S. Dept. of Agriculture. 




Bui. 1060. U. S. Dept. of Agriculture. 




Fig. I.— Riving for Clear Airplane Material. Fig. 2. Debris After 
Selective Logging. 



Bui. 1060, U. S. Dept. of Agriculture. 



Plate VIII. 




Basal Swell in Sitka Spruce in Alaska. 



SITKA spruce: uses, growth, management. 9 

unable to meet, caused the Spruce Production Division to encourage 
small isolated operations to rive out by hand cants of clear spruce 
from selected trees. By means of wedges and jacks huge logs were 
split to obtain cants of clear, straight-grained wood, which were 
dragged from the woods, usually by horses, and sent to resaw plants. 
(PL V, fig. 1). That method of logging was discarded later in 
favor of a plan of logging selected trees on a larger scale, and this 
method resulted in a more rapid production of high-grade spruce.* 
In logging selectively an ai'ea was combed of all trees which were 
of airplane quality, and the others were left standing. This method 
avoided the cutting of low-grade spruce and other timber for which 
there was no market. 

The cost of logging Sitka spruce has varied widely, more particu- 
larly during and since the war. Before the war the average cost of 
logging was about $5.50 per thousand feet; in 1919 it amounted to 
approximately $11 per thousand feet ; and in 1920 it was somewhat 
higher. 

Sitka spruce timber is normally cut into logs ranging from 32 
to 40 feet in length. As about 40 per cent of all timber cut on the 
Pacific coastal region is logged by ojjerators engaged solely in log- 
ging, who sell their logs in the open market, logs are graded accord- 
ing to size and quality into No. 1, 2, and 3 logs. It is estimated that 
Sitka spruce timber as logged will grade: Twenty per cent No. 1 
logs, 40 jDer cent No. 2, and 40 per cent No. 3. Prior to the war 
Sitka spruce logs sold for about $12, $9, and $6 per thousand for] 
No. 1, 2, and 3 logs, respectively. In 1920 they sold for $30, $24, and 
$18 on this basis. At the height of war-time operations in 1918 a 
price of $35 for No. 1 logs was reached. 

Most of the Sitka sj^ruce lumber that is manufactured in the 
United States is cut in the large band sawmills of the Coos Bay 
district of Oregon and the Grays Harbor and Willapa Bay districts 
of Washington. The sawmills of Alaska, with a daily capacity of 
25.000 to 40,000 board feet of lumber, are smaller com^jaratively. 

The cost of manufacture before the war was a little less than 
$5.50 per thousand feet; in 1919 it amounted to about $12, and in 
1920 it was a little higher. 

Although exceedingly high prices were paid in 1918 for clear 
lumber suitable for aii'craft construction, the average wholesale value 
of mill-run Sitka spruce in that year varied from $20 to $27 per 
thousand board feet. (See table 2.) Before the war an average 
price of about $14 obtained. Prices on January 1, 1919, are given 
in table 3. 

« " History of Spruce Production Dirlsion," 1919. 
85569—22 2 



10 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

Table 3. — Range in selling pi-ices of different grades of spruce lumber (/. o. ft. 
mill), January 1, 1919. . 
Grade. Price per 1,000 ft. b. m. 

"B" and better, finish, S2S $35.00 to .$62.00 

Factory select and better, S2S 35.00 to 62.00 

No. 1 shop, S2S 32.00 to 39.00 

Shop common, S2S 30. 00 

No. 2 shop, S2S 27.00 to 34.00 

Box, Nos. 1, 2, and 3, S2S 26.00 to 28.00 

Common boards. S2S 25.00 

Common dimension, SISIE 17. 50 to 30. 00 

Regarding the prices of Sitka spruce stumpage, it may be said 
that they varied as greatly in the last few years as did logging and 
milling costs. Ten years ago average stumpage was worth about 
$1.50 per thousand feet. Just prior to our entrance into the war it 
was about $2.75 per thousand feet, and in 1920 it reached $3.50. 
During 1918 stumpage values of selected trees to be cut in riving or 
logging operations ran as high as $7.50 per thousand feet. Sitka 
spruce stumpage, of course, like that of other species, varies in value 
with topography and accessibility. For this reason values greater 
than those given here, as well as values considerably less, have 
obtained. 

SIZE, AGE, AND DISTINGUISHING CHARACTERISTICS. 

SIZE. 

Sitka spruce, which is the largest of the spruces, grows to a size 
comparable with the maximum for Douglas fir and cedar, and larger 
than its other associates. 

When maximum sizes are considered, individual specimens of 
Sitka spruce have been found to attain surprisingly large propor- 
tions. Total heights of 296, 285, and 282 feet were recorded in the 
course of the field work for this study for individuals found in 
the vicinity of Quinault Lake and Beaver, Wash. All these trees 
were under 300 years of age. Specimens which measured over 9 feet 
in diameter at a height of 10 feet above ground were found not 
merely once or twice, but many times, in both Oregon and Washing- 
ton forests. The largest diameter recorded was of a tree which 
grew near Beaver, Wash. It measured 16 feet in diameter at 
breast height, and because of its gradual basal taper was of large 
volume (Pi. VI, figs. 1 and 2). Necessarily, large diameters and 
heights mean large volume, and individual trees in Oregon and 
Washington occasionally have scaled 40,000 board feet in merchant- 
able contents ; but the average tree scales about 8,000 board feet. In 
Alaska single trees have scaled 24,000 board feet of merchantable 
material.' 

• " Production of Airplane Lumber in Alaska," by W. G. Weigle, Alaska Pioneer, toI. 1, 
No. 2, p. 4, 1918. 



SITKA spruce: uses, growth, management. 11 

The species attains its maximum development in Washington and 
Oregon. The average tree found in the virgin forest has a height of 
about 230 feet and a diameter of i feet, measured 15 feet above 
ground. North of the optimum range in British Columbia it grows 
to maximum diameters of 8 to 12 feet and heights of 160 to 180 feet; 
but ordinarily it is only 3 to 6 feet in diameter.' In Alaska, too, its 
average diameter is 3 feet and its height about 150 feet, but single 
trees frequently exceed this. In California it is smaller than farther 
north and becomes only a medium-sized tree. This subject is dis- 
cussed more fully under the heading " Growth." 

LONGEVITY. 

Sitka spruce is a long-lived tree. Sudworth reports a maximum age 
of 750 years.^ During the recent study, however, the oldest tree that 
could be found was 586 years of age. It is doubtful whether many 
individuals ever reach an age of over 600 years, and the mean mature 
age is not more than 450 years. 

DISTINGUISHING CHARACTERISTICS. 

An outstanding characteristic of the appearance in the forest of 
Sitka spruce is its bark (PI. VII). The thin, stiiF, cupped, and 
elliptical dark purple-gray scales 1 or 2 inches in diameter make 
this species easily distinguishable from its associates in the stand. 
Little protection is aiforded to the living tissues, however, by the 
bark, which is only one-half to 1 inch thick. 

The needles are also of distinctive appearance. In spring the yel- 
lowish green color of new needles in sprays that bend downward 
limply at the ends of the branches stands out in contrast with the 
dark bluish green of the older needles ; and although the young leaves 
are soft and velvety to the touch, during the remainder of their 5 to 
6 year existence they are stiff and stand out straight in all directions 
around the twig, each needle tip being keenly pointed and quite 
bristly to the touch. The leaves are somewhat flattened, only indis- 
tinctly four-angled, and about 1 inch long. 

The cones, too, exhibit peculiarities by which this species may be 
identified. They have an average length of 3 inches, are light 
brown in color, ellijjtical in shape, and hang down conspicuously 
from the upper branches. The cone scales are thin and papery, 
with irregular margins but slightly pointed in general outline, and 
are firmly attached to the central stalk of the cone. Maturity is 
reached at the end of one year's development; soon thereafter the 
scales open and release the small dark brown seeds with their large 
thin wings adhering to them. Most of the cones drop from the 

« " Forests of British Columbia," by H. N. Whitford and R. D. Craig, p. 199, 1918. 
' " Forest Trees of the Pacific Slope," G. B. Sudworth, p. 83, 1908. 



12 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

tree soon after the seeds have been scattered by the wind, but some 
cones may remain on the branches for a number of years. 

The root system is characteristically shallow. This is especially 
true of trees on swampy soils where the roots spread out very close 
to the surface; but on deep, porous soils they penetrate 4 to 5 feet 
into the ground and occasionally as far as 12 feet. 

Characteristics of form are unimportant, with one exception, for 
the recognition of this siDCcies. In general, the forest-grown trees 
are tall, with open, conical crowns and long, cylindrical boles. 
Their bases are very commonly heavily buttressed. Plates VI (fig. 
3), YIII, and IX show the importance of this fact when form is con- 
sidered. Plate IX, figure 2, gives one clue to its cause; the stunips 
illustrated in this plate were those of only two out of seven fully 
grown trees that developed on this one windfall. Basal or butt swell 
is common in this species and especially so in trees which occur on 
the lowlands. Incidentally, it should be mentioned that this con- 
dition in the tree vei'j' materially affects any diameter measure- 
ments, for the standard practice in all species is to measure diameters 
at a uniform height of 44 feet above the ground, and this practice 
would give very inconsistent results with large Sitka spruces. 
Further discussion of this point appears under " Diameter gi'owth." 
'Ihe overmature trees present another characteristic, that of stag- 
headedness. (PI. VI, fig. 2.) Such broken-topped trees are apt to 
develop ascending side branches, and these may grow to 14 inches 
and more in diameter and 50 feet in height. Trees in this condi- 
tion, as shown by the cedar snags in Plate XIV, may be called 
bayonet-topped. 

OCCURRENCE. 

Sitka spruce stands are found on a variety of sites but may be 
grouped broadly into two classes — the bottomland or lowland, and 
the slope or highland. The development of the tree, which to a 
great extent is influenced by the amount of soil moisture, is the chief 
difference between the two types, and the altitudinal situation is of 
only minor consideration. The forest may be of pure spruce or of 
spruce in mixture with other species. These types occur throughout 
the range of the species, and a third or " upper slope " type might 
be added for Alaska to include the bodies of scrubby spruce near the 
upper altitudinal limit of tree growth. 

BOTTOMLAND TYPE. 

This type is found in the moist situations of river bottoms and 
benches above the river beds where there is a deep, rich alluvial soil, 
and where in places the heavy precipitation of the winter and spring 
months has so saturated the ground that standing water is not un- 



SITKA spruce: uses, growth, management. 13 

common. Here the trees, though large and tall, are characterized 
by large buttressed bases, limbiness, and comparatively short clear 
length. On these moist sites the trees make a noticeably rapid 
and well-sustained diameter growth, especially from 100 to 200 
j^ears of age. In this type Sitka spruce occurs also on tidelands 
and in swamps where there is considerable inundation ; but, although 
it can stand these conditions, it prefers an excess of soil moisture 
only with good drainage and in general avoids stagnant sites and 
acid soils. In contrast with the stands on the bottoms and benches, 
those in swamps are quite fi'equently pure, but the trees here are 
shorter and much more limby. Trees which occur on exposed situa- 
tions along the coast are small and scrubby and unfit for commercial 
uses. 

SLOPE TYPE. 

Spruce stands of the slope type are found on the moist but well- 
drained hills which border the lowlands and which afford all ad- 
vantages for excellent growth in their rounded ridges and gentle 
slopes of deep, rich soil. It is not only in the upland country that 
this type occurs; similar conditions exist on the rolling, sandy land 
along the coast. The trees on such sites are fine specimens, large and 
tall, with long, clear length ; and, in contrast with those of the bot- 
tomland type they seldom develop buttressed bases. (PI. XI.) The 
wood is characteristically fine-grained, and this fact is frequently 
mentioned by lumbermen as a means of distinguishing between trees 
of the two types. Spruce in these stands is more often pure than in 
mixture, and this is especially true on the sandy lands which border 
the ocean. (PI. XII.) 

COMPOSITION AND VOLUME OF STAND. 

Pure stands of Sitka spruce are usually not extensive but are apt 
to be limited to patches of a few acres in contrast with Douglas fir, 
which occurs pure over great areas. Larger pure forests of spruce 
are found occasionally, however, 40 or more acres in size in Oregon, 
Washington, and British Columbia, and even 100 acres in Alaska; 
but this is the exception rather than the rule. 

Wlien Sitka spruce grows in mixture with other species, the most 
common associate is western hemlock, and large areas of these two 
species are found in Alaska and in the States as well. Sitka spruce 
is also associated with Douglas fir, western red cedar, lowland white 
fir, silver fir, and Pacific yew throughout the range, with Port Orford 
cedar and redwood only in southern Oregon and California, and 
with Alaska cedar and mountain hemlock on the upper slopes in 
British Columbia and Alaska. In the valley bottoms it occurs with 
such hardwoods as broadleaf maple, black Cottonwood, and red alder. 
(PI. X.) 



14 



BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 



The composition of a typical piece of what is distinguished as the 
" western henilock-Sitka spruce type " in British Columbia is as 
follows : ' 

Per cent. 

Western hemlock 3S 

Sitka spruce 27 

Western red cedar ]5 

Balsam (silver) fir 15 

Others (Alaska cedar and Cottonwood) 5 

100 
A summary of cruises made in 1918 in spruce stands on the west 
side of the Olympic National Forest in Washington shows the fol- 
lowing average composition of the forest : " 

Per cent. 

Western hemlock 37 

Douglas fir 26 

Sitka spruce 21 

Silver fir 7 

Western red cedar 6 

Others 3 



100 

The mixed forest is usually of even age; infrequently it is of two 
age classes, and then the hemlock trees are the smaller and younger 
ones of the stand. An all-aged forest occurs but rarely, and then 
as an open stand on swampy soils. 

An idea of the composition of the stand and the representation 
of small-sized ti-ees of other species (in the older stands) may be 
gained from Table 4. This table shows the results of measurements 
on 12 sample plots in typical stands in Oregon and Washington 
in which Sitka spruce comprised from 50 to 100 per cent of the 
volume of the stand. 



-Nwmier of trees of Sitka spruce and other species per acre for typical 
stands of various ages. 



Plots. 


Living trees per acre. 




Area. 


Age. 


Sitka sprace. 


other species. 




Designation and locality. 


Under 12 
inches. 


Over 12 
inches. 


Under 12 
inches. 


Over 12 

inches. 


Total. 




Acres, 
0.4 
.2 
4.0 
2.0 
2.0 
4.0 
4.0 
4.0 
4.0 
5.2 
2.0 
2.0 


Years, 
27 
60 
70 
130 
175 
175 
240 
260 
290 
310 
320 
340 


448.0 
104.0 
1.5 
2.5 
1.5 
3.5 
.0 
.2 
.5 
.0 
3.0 
.0 


122.0 
112.0 
27.7 
61.0 
49.5 
13.2 
18.0 
18.2 
21.5 
10.1 
7.0 
7.0 


30.0 
24.0 
25.2 
3.0 
10.0 
13.8 
28.2 
5.3 
8.0 
.0 
43.5 
40.0 


0.0 
32.0 
98.0 

8.0 
13.5 
41.2 
18.8 

9.6 

8.0 
10.3 
54.0 
34.0 


600.0 




272.0 




152. 4 




74.5 




74.8 




71.7 




65.0 




33. J 




38.0 




20. « 




107. S 




81.0 







» " Forests of British Columbia," by H. N. Whlttord and R. D. Craig, p. 61, 1918. 
•"Descriptive Report of Olympic West Side Spruce," by C. J. Conover. Forest Service 
manuscript report, p. 13, 1918. 



stTKA spruce: uses, growth, management. 15 

The underbrush, which in both the pure and mixed forests is 
extremely large and dense, is composed of salmonberry, huckleberry, 
vine maple, salal, devil's club, elderberry, and cascara, with a pre- 
ponderance of the first two species. The ground cover consists chiefly 
of braken, sword ferns, and moss. 

The volume of sjDruce per acre in the virgin stand varies greatly 
with the proportion of species, the density of stocking, and the quality 
of the site. The heaviest yields are naturally i^roduced in properly 
stocked stands on sites where the best growth of individual trees is 
made. County cruise estimates indicate that the stand of merchant- 
able timber in what would be classed as spruce type (running all the 
way from 25 per cent to 65 per cent of spruce) varies from 20,000 to 
100,000 feet per acre over large areas. Very much heavier, as well as 
lighter, stands occur in the virgin woods. 

CLIMATIC AND SOIL REQUIREMENTS. 

Sitka spruce is very exacting in its soil and atmospheric moisture 
requirements. An abundance of rainfall, frequent fogs, and tempera- 
tures moderated by proximitj- to the sea are the climatic character- 
istics of the north Pacific coastal strip where this species grows. The 
yearly precipitation is 75 to 150 inches or more and comes chiefly in 
the form of rain, well distributed throughout the year, except for 
about two months in midsummer. Cloudy or partly cloudy days are 
frequent, and weather records show an average of 240 such days in a 
single year at one station in the heart of the spruce region. The tem- 
perature of the region is generally mild, the annual mean ranging 
from 38° F. in Alaska to 53° in northern California. Extreme tem- 
peratures of 15° below zero in Alaska and 102° above in California 
are encountered within the range of the tree ; but withal it may very 
readily be seen that Sitka spruce occurs only on areas that offer 
climatic advantages favorable for growth. 

Its soil requirements, however, are not so distinctly defined, and 
thin, rocky soils on the slopes, pure sand along the coast, and deep, 
rich alluvial deposits of rivers share equally, under similar condi- 
tions of climate, in the distribution of the species ; but the trees are 
larger and reach better development on bottom lands of moist, friable, 
sandy loam. It is noteworthy that in Alaska the heaviest stands of 
spruce and those of best quality are found on limestone soils, perhaps 
partly because these are the deepest and most completely decomposed. 
Though this species demands a very great amount of soil moisture 
and can grow on swampy sites, it attains its best development on soils 
of good drainage. 



16 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

LIGHT REQUIREMENTS. 

Sitka spruce, unlike other spruce, is somewhat intolerant of shade. 
Compared with its associates, it is less tolerant than western hem- 
lock and western red cedar and about as tolerant as Dou£flas fir. 
Seedlings can endure heavy shade and on old burns and logged-over 
areas establish themselves with little difficulty under the dense cover 
of deciduous brush, such as salmonberry and huckleberry, and of 
other coniferous seedling growth ; but strangely enough Sitka spruce 
is seldom found under the heavy canopy of a mature stand. Here 
temperature, not tolerance, is thought to be the governing factor, 
and the coolness in the mature stands prevents, whereas the warmth 
in the openings permits, the germination and establishment of spruce 
seedlings. As the tree advances in age it demands overhead light, 
and dies if long overtopped. 

The dead side branches, which are often moss-covered stubs 2 or 3 
feet long and characteristically coarse and stiff, are very persistent 
in young spruce. The shedding of the dead limbs and cleaning of 
the bole starts when the trees are about 50 years old and often is not 
completed for a century or more. (PI. XII and PI. XIII (fig. 1.)) 

REPRODUCTION. 

SEED PRODUCTION AND DISSEMINATION. 

Sitka spruce is a prolific seeder. Open-grown trees conunence to 
bear seed at 35 years of age, and trees of all sites are vigorous pro- 
ducers of seed until maturity. Some seed is produced each year 
and heavy crops are yielded every three or four years. The cones 
mature in the early fall of the first year and, under normal condi- 
tions, open and release the seed within a short period afterwards. A 
mature tree with a full crown may produce, in a good seed year, 4 to 
6 bushels of cones, which yield from 0.65 '° to 1.25 " pounds of clean 
seed. A pound of these seeds will number between 200.000 and 300,- 
000. Because of their small size and relatively large wings they are 
often carried by the wind 400 feet or more from the base of the tree. 
Many of the seeds filter into the deep duff of the forest floor and are 
stored, their hard covering keeping them viable for several years. 
The seed has a high percentage of germination. In tests " of fresh 
commercial seed under greenhouse conditions, this amounts to 72 per 
cent, and is higher than the germination percentage of western hem- 
lock, western red cedar, and Douglas fir as determined in similar tests. 

'» " Sitka Spruce In Alaska," by B. E. Hoffman. Forest Service manuscript report, p. 9 
1912. 

" " Reforestation on the National Forests," by C. B. TUlotson. U. S. Dept. Agr. Bull. 
475, p. 17, 1917. 

■^ " Seeding and Planting," by J. W. Toumey, p. 122, 1916. 



Bui. 1060. U. S. Dept, of Agriculture 




Fig. I.— Variation in Basal Swell. Illustrated by Trees in Left and 
Right Foreground. 




Fig. 2. — Stumps of Mature Trees Which Started on Old Windfall. 



3ul. 1060, U. S. Dept. of Agriculture. 




Sitka Spruce in Mixture With Red Alder and Broadleaf Maple on 
River Bottom. 



Bui. 1060. U. S. Dept. of Agricultur 




Highland Spruce at 1,100 Feet Elevation in Clatsop County. Oreg. 



U. S. Dept. of Agncultur 







Pure, Even-Aged Stand of Sitka Spruce (175 Years) Near Tsiltcoos 
Lake, Oreg. 



Bui. 1060, U. S. Dept. of Agriculture. 



Plate XIII 




Fig. I.— a Stand of 65- 
Year-Old Spruce WITH 
Uncleaned Boles. 



Fig. 2. Thrifty 18-Year-Old Sitka Spruce 
IN Old Clearing. 



Bui. 1060. U. S. Dept. of Agriculture. 



Plate XIV. 




Bui. 1050. U. S. Dept. of Agriculture. 




Fully Stocked Second-Growth Sr 



-YtAr,-ULu biiKA Spruce. 



ul. 1060, U. S. Dept, of Agricultur 




K -Nl.c M. 

Fig. 2. — Fruiting Bodies of Trametes Pini. 



SITKA spruce: uses, growth, maxagemext. 17 

ESTABLISHMENT OF SEEDLINGS. 



Sitka spruce germinates slowly, and in this habit it is similar 
to other low-altitude species of the coastal legion, and in contrast 
with Engehnann spruce and liigh-altitude Douglas fir, which re- 
quire only a short time for germination. Similarlj', Sitka spruce 
seedlings do not respond quickly to atmospheric warmth early in 
the sjjring, and their buds do not unfold until the season is well ad- 
vanced. Were it not for this characteristic much injuiw to re- 
production would result, for during early spring clear, warm weather 
in the lowlands is often followed by killing frosts. 

Moisture, light, and heat are all essential for the germination and 
establishment of spruce seedlings; but, as moisture is abundantly 
suj^plied by rains and fogs in the region, and as the young seedlings 
are capable of enduring dense shade, heat is the uncertain factor. 
In this regard the warm exposures of old burns, clearings, and 
logged-over lands offer conditions more suitable for growth than 
elsewhere, and, as spruce can compete successfully with all other 
species, it establishes itself with little difficulty on these sites. In 
the choice of seed bed, Sitka spruce prefers loose mineral soil, but 
it can thrive equally well in the tlecaj^ed wood of down logs and in 
the deep humus of the forest floor. Plate -IX, figure 2, illustrates 
the establishment of two spruce trees on an old windfall. Because 
of its extreme tolerance in early youth, Sitka spruce sometimes. occurs 
on fresh earth slides, under a temporary cover type of alder, and 
eventually liecomes the predominating species. 

Stands of reproduction in the spruce type are densely stocked. 
(Pis. XIV and XV.) Counts were made during the recent field 
study on 10 square-rod quadrates in areas of reproduction, and these 
counts showed that in thrifty stands under 10 years old there were 
3.000 seedlings per acre, and that in stands 30 years old there were 
500 trees jier acre. Nearly one-quarter of the 30-year-old trees were 
12 inches and over in diameter at breastheight. It was also shown 
that a stand of maximum density, which was 5 years old, contained 
35.000 seedlings per acre. In each of these stands 50 per cent or 
more was spruce, and the remainder was mostly hemlock, with a 
few cedar and Douglas fir trees. In very dense stands Sitka spruce 
seedlings generally comprise only 10 to 20 per cent, but this per- 
centage often increases as the stands become older. Under ordinary 
circumstances spruce is able to maintain itself and even increase 
notwithstanding the competition of other species. These seedlings, 
which are rather delicate and slender stemmed during the first few 
vears, later develop heavy, stiff stems. They at first average nearly 
one-half foot in height growth per year and beyond 15 years of 
age increase in height at the rate of 3 feet per year. 
85569—22 3 



18 BULLETIN 1060, IT. S, DEPARTMENT OF AGRICULTURE. 

CAUSES OF INJURY. 

FUNGI." 

Sitka spi'uce, in common with other forest trees, is attacked by 
two broad groups of fungi — first, those reducing the annual incre- 
ment ; and, second, those reducing the merchantable timber. 

In the first group there are two rust fungi. One of these is a broom- 
forming rust {Peridermium- co7oraden.se). The mycelium of the 
fungus is perennial in the twigs of the host, causing pronounced 
witches' brooms. As a rule, this fungus is not serious, but it may 
completely dwarf and deform small trees. 

The other rust fungus {Peridermium decoloi^ans) does not cause 
any deformation of the host. The mycelium confines itself to the 
infected needles and does not enter the twigs or branches. The 
parasite is usually confined to small trees of the sapling and small- 
pole sizes. 

Another needle disease of importance is characterized by a brown- 
ing of the individual needles. This fungus is Lophodennrnm macro- 
sporum or a closely related species. Infected needles are invariably 
killed and drop off, but the degree of infection varies. Sometimes 
only occasional needles are diseased; at other times most of them 
may be killed. The disease usually attacks the lower branches of 
j'oung trees. It has been reported as very prevalent along the lower 
Columbia Eiver in Clatsop County, Oreg. 

It is impossible to give an estimate of the amount of damage 
caused by the needle and twig diseases just mentioned. It is obvious 
that there must be a greater or less reduction in annual increment 
of the infected trees, but no exact data are available. Control meas- 
ures need not be discussed, as present economic conditions preclude 
such work, except for nursery stock or trees of high aesthetic value. 

By far the most important fungi are those which reduce the mer- 
chantable volume by attacking and destroying the heartwood of 
living trees. 

The most serious of these on Sitka spruce is the ring-scale fungus 
(Trametes pini) which causes the common red rot or conk rot in tlie 
heartwood of living trees. In spruce the attack may be made at any 
point along the bole. In the split section the decayed wood has a 
reddish color in its early stages, and later small white sunken spots 
are found separated by apparently sound reddish wood. The fungus 
gains entrance to the heartwood of the trees principally through old 
branch stubs and is exceedingly destructive in mature and over- 
mature stands. Plates XVI' (fig. 2) and XVII are illustrations of 
this fungus. 

Next in importance is the velvet-top fungus {Polyporus sckicei- 
nitzii), which causes a pronounced butt rot. The sporophores ap- 

" Prepared in collaboration Willi Dr. J. S. Boyce, Pathologist, Bureau of Plant Industry. 



SITKA spruce: uses, GEOWTH, MANAGEME>'T. 19 

pear at the base of the tree, on the trunk in okl wounds, or on the 
ground, coming up from decayed roots. Those on the ground have a 
short, thick stalk. The disease spreads both by spores blown about in 
the air and through the ground by means of the decaj^ed roots. The 
decay which is confined to the heartwood is light reddish brown in 
the early stages, and pronouncedly cubical, reddish brown, crumbling 
to a fine powder between the fingers, and often with thin resinous 
(rusts of mj'celium in the typical stage. The rot is found in the roots 
and butt, and rarely extends beyond the first log. Besides the actual 
loss due to the volume of wood rendered unmerchantable by decay, 
the infected tree is frequently broken off at the base as a result of the 
weakening of the roots. Many large overmature trees, completely 
rotted at the base except for a thin layer of sapwood. are found broken 
off between 5 and 20 feet above ground, and their loss can be charged 
directly to the destructive work of this fungus. 

The red-belt fungus {Fomes pinicola) is of equal importance with 
Polyporus sehweimtzll as a butt rot in living trees; but it is also 
common on dead snags, old windfalls, stumps, and other debris, and 
thus functions as a beneficial scavenger in the forest. The fruiting 
bodies are usually found at the base of the tree in the flare of the roots 
or at scars along the lower portion of the trunk. The typical decay 
is light reddish-brown in color, somewhat cubical, crumbly and 
brittle, with white feltlike layers of mycelium occupying the cracks. 
Infection caused b}' this fungus is illustrated in Plate XVI. figure 1. 

One of the most common fungi found on fallen Sitka spruce, be- 
sides the red-belt fungus, is the lacquer-top fungus {Ganoderma 
oregoneiise) , readily recognized by the shiny, lacquerlike, reddish 
upper surface of the annual fruiting body. This organism has not 
been reported on a living spruce, but is often found on its associate, 
the hemlock. There are a number of other fungi of less importance 
which live on fallen trunks, but do not attack living trees. 

Sitka spruce is much freer from decay than either western hem- 
lock or Douglas fir, but snags and down timber decay very rapidly. 
The earliest infection appears in trees between GO and 100 years of 
age; only a slight amount of rot is found in stands between 150 
and 300 j'ears of age, and this is confined to the butts of trees. Over 
300 3'ears, or after maturity, however, the tops commonly break off, 
and top rot as well as butt rot is very prevalent, becoming more 
marked with age. It is not unusual, however, to find trees of 400 
years entirely sound at the butt and with very little decay along the 
trunk or in the top. In general, this species is remarkably free from 
decay up to 200 years of age. 

The amount of resin which the wood of a tree contains, or that 
it is able to produce to cover any injury, affects its ability to ward 
off disease. Spruce, which has very little resin, is almost never able 



20 BULLETIN Ul«0, U. S. DEPARTMENT OF AGRICULTURE. 

to heal over scars or wounds along the bole ; here the spores of fungi 
soon establish themselves and, on account of the very moist condi- 
tions in spruce stands, cause the rapid decay of much sound wood. 

Advance rot spreads quickly in this species, and, though often 
hard to detect, it becomes very noticeable after lumber is dried. It 
is commonly, though not always, accompanied by a change of color 
in the wood, appearing as streaks of red, yellow, or green. Tests 
were made recently by pathologists to show the effect of different 
stages of decay on the strength of the wood, particularly for spruce 
airplane stock, but these data are not yet available for publication. 

INSECTS." 

Although Sitka spruce, like other forest trees, is subject to insect 
attacks, it is not so susceptible as most of its associates in the forests 
of the Pacific coastal region. The attacks are naturally more serious 
in pure or nearly pure stands of Sitka spruce than in stands in which 
it occurs in mixture. Damage is caused by three classes of insects — 
bark beetles, defoliators, and borers. The first two classes attack 
standing timber and the last works in felled trees. 

The most important insect enemies of Sitka spruce are the bark 
beetles, of which the most destructive is the Sitka spruce beetle 
{Dendroctoims obesiis). This beetle attacks the living trees and 
kills them by girdling in the cabium layer. In attacking the trees 
the first broods enter the inner bark of the middle trunk, and those 
which appear later extend the infestation to the base of the trunk 
and even to the larger roots. This beetle also works in the inner 
bark of stumps, logs, and slash of felled trees. Although no e.xten- 
sive depredations of the Sitka spruce beetle have been found thus 
far, it has been reported now and then that groups of Sitka spruce 
have been killed by its activity. If infestations should ever become 
widespread it would be possible to practice control operations by 
cutting and barking the infested trees before the beetles emerge in 
the late spring. It would not be necessary to burn the bark in this 
work.^^ 

From time to time Sitka spruce is subject to the attacks of such 
defoliators as caterpillars, sawfly larvae, and aphids, all of which 
destroy the needles and may therefore occasionally kill trees over 
lai-ge areas. In Clatsop County, Oreg., in 1890 and 1891, Sitka 
spruce and western hemlock were attacked and killed over an area 
of thousands of aci-es by a caterpillar belonging to the Geometrid 
family. During the years 1917 to 1920 the Sitka spruce and western 
hemlock on several hundred thousand acres on the Tongass National 

" Prepared in collaboration witii Forest Examiner A. J. Jaenicke, U. S. Forest Service. 

»' For detailed information regarding control measures, see Bulletin 83, Part I. " Bark 
Beetles of tbe Genus Dendroctonus," by A. D. Hopkins, Bureau of Entomology, U. S. De- 
partment of .-igriculture. 



siTKA spruce: uses, growth, management. 21 

Forest in southeastern Alaska were defoliated by the combined activ- 
ity of sawfly hirvas and catei'pillars belonging to the Tineid family. 
Thus far only a small portion of the Sitka spruce in southeastern 
Alaska has been killed by this widespread defoliation. 

Occasionally aphids kill the foliage of Sitka spruce. The western 
spruce gall louse {Aphis abietina) is believed by Dr. A. D. Hop- 
kins of the Bureau of Entomology to be the aphid which caused 
the loss of the needles of Sitka spruce over thousands of acres of 
forest in 1918 in various portions of the coast region in Oregon 
and AV'ashington. Fortunately the activity of this aphid was of 
extremely short duration, and only about 1.5 per cent of the in- 
fested spruce was killed. Most of this loss was confined to swamp 
and tideland areas in the lower Columbia River basin and the 
coast region and included only the poorer stands of timber. The 
Sitka spruce gall aphid {Chermes cooleyl) is found very commonly 
doing injury to Sitka spruce reproduction and occasionally causing 
its death. Large trees also are attacked, but the injury to them 
is rarely severe. These minute insects cause the development of 
conelike galls which kill the aU'ected twigs. Infested trees of special 
value, such as those in parks and streets, may often, with good results, 
be sjjraycd with contact sprays like kerosene emulsion. 

Fortunately the work of defoliators does not continue more than 
a few years when it is controlled by natural agencies. Under forest 
conditions control measures against this class of insects are not 
feasible. However, defoliators greatly increase the fire hazard on 
the areas on which they have been active. Nearly always the fires 
which followed the defoliators did more damage than the insects 
themselves. The reduction of the fire risk on the defoliated areas 
is, therefore, an important consideration in defoliator problems. 

Felled timber of Sitka spruce is subject to the attacks of various 
wood borers. Logs cut between April and September are frequently 
attacked, shortly after being felled, by ambrosia beetles, sometimes 
called timber beetles or pinhole borers. These are small, elongate, 
wood-boring beetles which excavate round black tunnels, the di- 
ameter of a pencil lead, into the wood of dying trees and stumps, 
as well as logs. Investigations by the Bureau of Entomology in 
1919 showed that species of Gnathothrichus and Xyloterus commonly 
attack Sitka spruce logs, as well as western hemlock and Douglas 
fir. These borers may penetrate the wood to a depth of from 4 
to 6 inches and therefore seriously reduce the value of the sapwood, 
especially when Sitka spruce is being used for such special pur- 
poses as airplane stock. The logs which are cut in the late fall and 
winter are usually attacked in the following spring. Logs cut in 
the early fall are not entered that season; and, if piled loosely in 



22 BULLETIN 1060, U. S. DEPARTMENT OF AGEICULTUKE. 

the open, they often dry sufficiently to be protected from attack the 
following spring. Logs placed in water are safe from further in- 
jury. Damage by these borers can be prevented almost entirely by 
removing the logs from the woods or placing them in water as soon 
as they are cut. 

Larger wood borers are an important factor in the deterioration 
of the sapwood and heartwood of fire-killed trees and logs. During 
the first two summers after the death of the trees or the felling of 
the trees the borers are most active, and at the end of the two-year 
period the salvage value is usually next to nothing. If the logs 
are placed in water or barked within a few weeks after cutting, losses 
by these borers may be avoided. Logs which are loosely piled in 
the open soon after cutting usually escape damage because of the 
rapid drying out of the thin bark, which is then unattractive to the 
borers for the laying of eggs. Dr. J. M. Swaine, of the Canadian 
Entomological Branch, recommends covering the logs thickly with 
brush. The logs to be covered should be piled on skidways and 
given a very thick covering of green limbs so that the sunlight can 
not penetrate at all to the logs beneath. 



Sitka spruce, because of its characteristically sliallow root system, 
can not withstand severe winds. Trees which grow on exposed 
situations along the coast where they encounter severe winds are 
windfirm, but they are also scrubby and of little use for lumber. In 
the virgin forests under normal conditions only the very diseased 
trees are likely to be wiudthrown, but in cut-over ai'eas trees isolated 
by logging and those which border on fresh cuttings are invariably 
windthrown. (PI. XVIII.) Spruce trees which have grown in 
dense stands never become wind-resistant, and full consideration 
must be given this fact before a method of cutting and a man- 
agement policy are adopted for a spruce forest. 

The hurricane that swept the western edge of the Olympic pen- 
insula, Washington, in January, 1921, felled from 5 to 95 per cent 
of the timber on a swath 60 miles long and 20 miles wide in the 
heart of the spruce belt. Six billion feet or more of virgin western 
hemlock, Sitka spruce, Douglas fir, silver fir. and western red cedar 
timber was laid flat by the wind. Perhaps a billion feet of Sitka 
.spruce in the State of Washington was windthrown in that stoi-m. 
All species suffered alike regardless of their relative windfirmness. 

In addition to windthrow, other damage from the elements is 
wrought upon spruce timber by breakage and wind-shake. The 
breakage consists in the shattering of the tops of overmature and 
decadent trees, and this permits the entrance of fungous growth. 



SITKA spruce: uses, growth, makagemejtt. 23 

whirh spreads quickly through the sound wood and renders much 
of the ujjper trunk unmerchantable. Damage from this cause is 
\ery common in trees over 300 years of age. Wind-shake is a me- 
clianical defect resulting from heavy stresses in the butt section 
wliich are caused by the action of severe winds, and is of infrequent 
occurrence in large trees. This circular or radial rupture of the 
wood considerablj' reduces the value of the tree for lumber. 



Another injury is the formation of huge burls along the trunks. 
This defect has been found abundantly in a limited area in Oregon. 
The illustrations in Plate XIX are typical examples of the defect. 
Its cause is uncertain, though probably analogous to similar mal- 
formations in many other species. 

FIRE. 

Sitka spruce is fortunate in having as its habitat a region in 
which there is less forest-fire hazard than in most parts of the conif- 
erous forest regions of western North America. Frequent rains 
throughout the year in southeastern Alaska make fires in the virgin 
si^ruce woods there quite uncommon ; farther south in Washington 
and Oregon there is more danger of forest fires in the short dry 
season. Fires in this region are apt to run in the crowns of the 
trees, and they do so even in the spring months when the surface 
litter is still too wet to burn. The moss that hangs on the branches 
of the hemlock, spruce, and fir trees is very inflammable and helps 
to carry fire. The spruce region of Oregon suffered from several 
ver}^ disasti'ous and widespread fires a few decades ago, as the 
" burns " of the Coast Kange witness. 

Sitka spruce is very susceptible to fire. This is due chiefly to its 
thin bark, which at stump height is only a half-inch to an inch 
thick. Fire-scars are uncommon in Sitka spruce, for even a very 
light surface fire is sufficient to kill the cambium, and the trees, 
thus girdled, die. 

Although an individual tree of Sitka spruce is more susceiDtible 
to injury than a Douglas fir of the same size, the forest in which it 
grows along the coast is less subject to fire than the forest farther 
inland where Douglas fir predominates. Even though the danger of 
uncontrollable fires is less in the Coast Range than in the Cascade 
Range, careful fire protection in both regions is imperative. 

GROWTH. 

Sitka spruce is one of the most rapid-growing coniferous species 
in the Pacific Northwest. In keeping with the character of spruces 
in general, its growth during the first few years is less than that of 



24 



BULLETIN 1060, V. S. DEPARTMENT OP AGRICULTURE. 



many other conifers; but thereafter it increases in size with great 
rapidity and maintains a fast growth until late in life. Its rate of 
growth naturally varies with the quality and the character of stand. 
Moisture conditions are an important factor and growth is more 
rapid on wet bottomland situations than on the drier slopes. The 
growth of Sitka spruce varies also in different parts of its range, and 
is more rapid in Oregon, Washington, and British Columbia than 
either farther south or north. Average figui-es on height, diameter, 
and volume growth are given in the tables that follow, but it is real- 
ized that these are not universally applicable. In the appendix will 
be found tables of growth from several different localities. 



In the seedling stage the height growth of Sitka spruce is fairly 
rapid, but not so fast at this period as that of its associates, Douglas 
fir, western hemlock, and western red cedar. Table 5 shows the 
height growth of dominant, open-grown Sitka spruce seedlings, and 
is compiled from measurements taken of young trees which grew in 
seven different localities and sites in Oregon and Washington. Here 
the reproduction was sometimes found in pure stands, but more often 
in mixture with other species. 

Table o. — Height of dominant, open-firoirn SUka spruce se^rdliiigs, averaged for 
all sites in Oregon and Washington. 

[Based on 2,102 sectional measurements of 322 trees.] 



Age. 


Height. 


Current 
amiual 
growth. 


Age. 


Height. 


Current 
annual 
growth. 


Years. 
I 


Fe<t. 
0.2 
.5 
1.0 
1.6 
2.2 
2.8 
:i. .5 
4.4 
5.4 


Feft. 
0.2 
.3 

..i 

.6 
.6 
.6 
.7 
.!) 
1.0 


10 


Years. 


Feet. 
6.6 
8.0 
9.8 
12.0 
14.4 
17.2 
20.2 
23.4 


Feet. 
1.2 












1.8 






2.2 






2.6 


6 




2.8 


7 




3.0 


8 


17 . . 


3.2 


9 











After the early years, growth increases rapidly and is maintained 
at a good rate until late in life. In the sapling stage a growth of 3 
feet and over a year is not unusual. At the age of 50 the average 
dominant tree is still growing 1.7 feet per year, and at 100 years as 
much as 1 foot. At these ages the height growth of spruce compares. 
very favorably with that of Douglas fir. This comparison is made 
from the available growth tables for the .species mentioned, under con- 
ditions representative for each species, and not by comparison of the 
several species growing side by side on the same site. 



3ul. 1060, U. S. Dept. of Agricultu 



Plate XVII. 




Bui. 1060, U. S, Dspt, of Agncultur' 



Plate XVI 1 1. 




Bui. 1060. U. S. Dept. of Agriculture. 



Plate XIX. 




Fig. 2. — Huge Burls Common 
Along the Coast Near 
Newport. Oreg. 



F— XM' |u 

Fig. I. — Abnormal Growth in Spruce. 



Jl. 1060, U. S. Dept. of Agr' 




SITKA spruce: uses, growth, management. 



25 



The figures given in Table 6 indicate the average total height and 
average annual height growth in each decade of older spruce of vari- 
ous ages, averaged from the measurement of 554 dominant ti-ees. The 
figures are dependable for trees iip to 300 years; beyond that age 
reliable height-growth figures are difficult to obtain, because very old 
spruce trees are commonly stag-headed. 

Table 6. — Average total height at various ages, and average annual height 
growth in each decade of Sitka spruce on all sites in Oregon and ^yashington. 

[Based on 1,260 sectional measurements (if 554 dominant trees.] (Curved.) 



Age. 


Average 

total 
heigtit. 


Average 
annual 
height 
growth 
in each 
decade. 


Age. 


Average 

total 
height. 


Average 
annual 
height 
growth 
in each 
decade. 


Years. 
20 


Feet. 
31 
51 
70 
87 
104 
119 
132 
144 
154 
164 
173 
181 
188 
194 
200 
205 
210 
214 
218 
221 


Fed. 
2.4 
2.0 
1.9 
1.7 
1.7 
1.5 
1.3 
1.2 
1.0 
1.0 
.9 
.8 
.7 
.6 
.6 
.5 
.5 
.4 
.4 
.3 


Years. 
220 


Fed. 
224 
226 
228 
230 
232 
233 
234 
235 
236 
236 
236 
237 
237 
237 
237 
237 
238 
238 
238 


Feet. 


30 


•230 




40 . . 












60 






70 


270 




80 


280 




90 






100 


300 . 




110 






120 


320 




130 




I__ 


HO 




J 


150 




2^ 


160 






170 


370. 


1 


180 






190 


390 


2_ 


200 






210 











DIAMETER. 



Diameter growth in this species is remarkably rapid and well sus- 
tained, as the figures in Table 7 indicate. In this table the figures 
represent the average of measurements taken of 557 dominant trees 
from seven localities in Oregon and Washington. Although its an- 
nual rate of diameter growth culminates at about the age of 40 years, 
it maintains a growth of over 3 inches per decade up to about 60 
years, and thereafter for a few decades over 2 inches per decade. At 
the advanced age of 400 years, the data in Table 7 indicate, the 
diameter is still increasing at the rate of over 1 inch per decade. 
Exceptionally rapid diameter growth is attained on wet sites, where 
sometimes it may amount to three-quarters and even 1 inch annually 
during early years of vigorous growth. Plate XX shows the 
diameter growth of Sitka spruce. 



26 



BULLETIN lOGO, U. S. DEPAKTMENT OF AGRICULTURE. 



Table 7. — Aicrui/r iVuniiitii mitsidc bark at 15 feet above pround at various 
ages and ini-niiji <uiiniiil ilitiiiniir growth in each decade of Sitka spruce 
groiving on nil .sihs iji ominn and Washington. 

[Based on measurement of 557 dominant trees.] (Curved.) 



Age. 


.\verage 
diameter. 


Average 
annual 
diameter 
growth 
in each 
decade. 


Age. 


Average 
diameter. 


Average 
annual 
diameter 
growth 
in each 
decade. 


Years. 
20 


Inches. 
2.0 
5.6 
9.5 
12.8 
15.7 
18.2 
20.5 
22.5 
24.4 
26.3 
28.1 
29.9 
31.5 
33.1 
34.7 
36.2 
37.7 
39.2 
40.6 
42.0 


Inches. 


Yean. 
220 


Inches. 
4:i.4 
44.8 
46.2 
47.5 
48.8 
50.1 
51.4 
,52.7 
.54.0 
55.3 
.56.6 
57.8 
59.0 
60.2 
61.4 
62.5 
63.6 
04.7 
65.8 


Inches. 
0.14 


30 . . . 


0.36 
.39 
.33 
.29 
.25 
.23 
.20 
.19 
.19 
.18 
.18 
.16 
.16 
.16 
.15 
.15 
.15 
.14 
.14 


230 




40 






50 


250 


.13 


60 




.13 


70 




.13 


SO 


280 


.13 


90 


290 


.13 


100 


300. 


.13 


110. ... 




.13 


120 




.13 


130 


330 . 


.12 






.12 


ISO 


350 


.12 


160. . . 


360 


.12 






.11 


180 


380 


.11 


190 




.11 


■200 


400 


.11 


210 











Diameter measurements at breast height are of little value in a 
Sitka spruce growtli study, as this species commonly has a pro- 
nounced basal swell and its root base is usually well above the gen- 
eral ground level, owing to its habit of starting on down logs. For 
these reasons, in Forest Service timber survey work in spruce, diam- 
eters are taken at a point 1 foot above the swell ; but this is a variable 
height and can not be used in growth studies when the relation be- 
tween age and diameter is desired. In Table 7, therefore, diameters 
are given for a distance 15 feet above the ground and on most trees 
this point is above the basal swell. It must be borne in mind, how- 
ever, that this uniform height above ground does not mean a uniform 
distance between this point and the root bases of all the trees meas- 
ured. Trees which started on fallen logs 4 or 5 feet in diameter 
naturally have their root bases 4 or 5 feet above the ground, and the 
number of annual rings showing at the 15-foot point in these trees 
is, of course, less than at this point on trees whose root bases rest 
on the ground. It was found, however, that the discrepancy for all 
the trees measured amounted to only two years. This variation is 
rendered of little consequence by the rapid height growth of Sitka 
spruce in its sapling stage, when 3 feet per year is not an unusual 
growth. Another point that mvist be kept in mind in this connec- 
tion is that it takes an average of 14 years for the seedling to reach 
a height of 15 feet, as shown by Table 5, and therefore a tree must 
be more than 14 years old before it shows diameter at this point of 
measurement. 



SFTKA spruce: USES, GROWTH, MANAGEMENT. 



27 



The volume growth of Sitka spruce is also rapid and well sus- 
tained. Table 8 indicates tlie average diameter, height, and volume, 
and the average volume growth that may be expected of dominant 
Sitka spruce trees in the spruce region of Oregon and Washington. 
The figures for diameter, height, and board-foot volume were taken 
from Tables 6, 7, and 11. Those for cubic-foot volume were sup- 
plied from a tree diagram in which the figures for average diameters 
and heights w^ere combined with complete stem analyses of 10 domi- 
nant trees. 

As indicated in this table, tlie periodic annual volume increment 
of spruce at 100 years exceeds 5 cubic feet, and at 300 years it is 
double this amount. The periodic annual growth continues greater 
than the mean annual for a long time after 300 years. At 100 years 
of age tlie volume of the entire stem witliout bark of dominant Sitka 
s^jruce trees approaches the high figure of 300 cubic feet, and at 200 
and 300 years it exceeds 1,000 and 2,000 cubic feet respectively. 

Table 8.- — Average diameter, height, wnd volume and average volume growth of 
do7ninant Sitka spruce trees in Oregon and Washington. 





Si 


ie. 


Volume. 


.\miual volume growth. 


Age. 


D. 0. b. 
at 15 tt. 


Total 
height. 


Entire 
stem 

without 
bark. 


From 
stump 
height 
to top 
d. i. b. 

of 10 
inches. 


Periodic. 


Mean. 


Periodic. 


Mean. 


5 "ears. 


IlichiS. 

2.0 
9.5 
15.7 
20.5 
24.4 

2S.1 
31.0 
Ji4.7 
.37.7 
40.fi 

43.4 
4i;.2 
48. S 
51.4 
54.2 


Feet. 
31 
70 
104 
132 
154 

173 
188 
200 
210 
218 

224 
228 
232 
234 
23B 


Cu./t. 
3 

22 
87 
175 
279 

400 
538 
fiOO 
859 
1,036 

1,219 
1,417 

1,617 
l,81S 
2,020 


Bd.ft. 


Cu-.ft. 
0.15 
.9 
3.2 
4.4 
5.2 

6.0 
6.9 
7.6 
8.4 
8.8 

9.2 
9.9 
10.0 
10.0 
10.1 


Cu.ft. 
0.15 
.5 
1.4 
2.2 
2.8 

3.3 
3.8 
4.3 
4.8 
5.2 

5.5 
0.9 
6.2 
6.5 
6.7 


Bd.ft. 


Bd.ft. 


40.. . 








00 


260 

670 

1,230 

1,960 
2,760 
3,690 
4,640 
5,660 

0,720 
7,800 
8,940 
10, 040 
11,170 






80 


20 
28 

36 
40 
46 
47 
■51 

53 
54 
57 
55 
56 


8 




12 


120 


16 


140 

100 . 


20 
23 




25 


200 


28 


220 


30 




32 


260 


34 




36 


300 .... 


37 







YIELD. 



The yield of Sitka spruce per acre in the virgin forest varies con- 
siderably with its representation as a species in the stand, with the 
density of stocking, and with the quality of site. Although available 
data are not suiRcient to furnish yield tables for the wide range 



28 



BULLETIN 1060, V. S. DEPARTMENT OF AGRICULTURE. 



of conditions which obtain in the virgin forest, it is possible to give 
an idea of what may be expected under average conditions. The 
number of trees and the yield per acre in Table 9 are based on the 
averaged and curved values of twelve sample plots from one-half to 
5 acres in size. On six of these plots Sitka spruce made up 88 to 
100 per cent of the stand by volume ; on five of them it made up 50 to 
82 per cent, and on one plot it comprised 25 per cent. The plots 
were in essentially even-aged stands, except that the older stands 
contained an underwood of younger hemlock and cedar trees. 

Tahle 9. — Average yield per acre o/ stands of Sitka spruce and associated speciesi 
on good quality sites in Orepon and Washington. • 

(CurTed ) 



Age. 


Trees 
per 
acre. 


Yield 
per 
acre. 


Mean 
annual 
growth. 


Age. 


Trees 
per 
acre. 


Yield 
per 
acre. 


Mean 
annual 
growth. 


40 


400 
280 
220 
175 
130 
112 
94 


Boardfeet 
29,500 
M,260 
78,000 
99,500 
115,000 
126,000 
134,000 


Boardfeet 
734 
904 
975 
995 
958 
900 
838 


Years 
ISO 


82 
70 
60 
50 
42 
36 
30 


Boardfeet 
140,000 
144,750 
148,250 
151,000 
153, 000 
154,250 
155,500 


Boardfeet 








80 


220 


674 


100 












140 


280 

















As represented by the figures in this table, the yield of spruce 
stands compares well with that of Douglas fir on the best sites. Up 
to 90 years it makes a better yield, at 100 years it equals, and there- 
after it falls a little behind Douglas G.r.^'^ The yields of the table 
are those of the virgin forest; if proper methods of forest manage- 
ment were employed, and if the trees were thinned at regular inter- 
vals, these yields would be considerably increased. The rapid incre- 
ment of Sitka spruce is especially evident when the periodic annual 
growth is considered, which between the ages of 40 and 60 years is 
1,237 board feet. 

MANAGEMENT. 

Since Sitka spruce does not ordinarily grow in pure stands, but 
rather in intimate mixture with several other commercial trees, the 
principle of management which must be applied to spruce should be 
equally applicable to its associates — ^fir, hemlock, and cedar. The 
entire forest of which Sitka spruce forms a part must be treated uni- 
formly. Hence the discussion of the management of spruce is inter- 
woven with considerations of the other trees in the stand. 

It has been shown that Sitka spruce is a very excellent timber tree, 
that its wood is superior to that of all others in the region for certain 

" Manuscript report by E. J. HanzUk, Forest Service, Mar. H, 1912. 



SITKA spkuce: uses, growth, management. 



29 



purposes, that the tree has habits of growth and hardiness that rec- 
ommend it as a tree for the forester to favor and propagate for the 
forests of the future. It should be the objective, theiefore, of tim- 
bermen and foresters so to manage spruce lands that they may be- 
come reforested through natural seeding, and that the new crop may 
contain a desirable admixture of Sitka spruce wherever this species 
will thrive. 

Much of the land upon which the virgin forests of spruce occur 
has agricultural value and will be put to that use after the removal 
of the timber. On such lands no effort need be made by the forester 
or lumberman to pi'omote a new crop to take the place of the one 
removed, but on all other lands this should be done. 

The rapid extension of logging operations in this type makes very 
timely a discussion of methods of forest management which will in- 
sure continuous crops of timber. 

OWNERSHIP. 

The present oAvnership of the commercial Sitka spruce is shown in 
Table 10. 



-Ownership of SUka spruce tim1)er, by classes of oimiers, in millions 
of feet, hoard measure. 



Ownership. 


Wash- 
ington. 


Oregon. 


ro'r^. Alaska. 


British 

Co- 
lumbia. 




1,550 

720 
4,205 


300 
4,074 


1S7 


15,000- 
18,000 










1,423 




m 


12,742 






6,475 


4,374 


187 


15,000- 
18,000 









1 Including Indian reservation. 



' Negligible amount. 



From the above it is seen that in Alaska the Sitka spruce forests 
are practicallj'^ all under Federal control, but that in Washington, 
Oregon, and California the bulk of this timber is in private owner- 
ship. The perpetuation of forests of Sitka spruce and their future 
welfare are largely in the hands of private owners and not under 
the jurisdiction of public agencies of government. Many of the hold- 
ings have been consolidated into units of 1,000 to 30,000 acres, though 
small properties are not uncommon. The State lands of Washington 
are in various-sized blocks, which in the aggregate now amount to 
about 10,000 acres. The Sitka spruce timberlands under Federal 
control in Washington lie chiefly in the Olympic National Forest and 



30 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

in the Quinault Indian Eeservation. In Oregon they are confined 
to the Siuslaw National Forest and several military and lighthouse 
reservations. 

FIRE PROTECTION. 

The most important factor in the management of the Sitka spruce 
type is fire protection. Without effective fire protection all other 
steps in forest conservation are useless. The virgin forests of the 
Sitka spruce type in the coastal belt are perhaps less likely to suffer 
from fire than the Douglas fir forests of the Cascade Range, but they 
are by no means immune. Systematic organized fire protection dur- 
ing the two or three dry summer months is essential for the safety 
not only of the virgin forest but also of the new crop of reproduc- 
tion which follows logging. In the course of lumbering, special 
precautions should be taken by operators to prevent the escape of 
fire, for an accidental and uncontrolled fire in dry slashings may gain 
such headway that it will do great damage to adjoining standing 
timber and especially to areas of second-growth timber on older 
cuttings. 

METHOD OF CUTTING. 

Clear cutting is the method of logging universally employed in the 
spruce region ; it is the only method practicable in these dense forests 
of very large trees. Moreover, Sitka spruce and western hemlock 
when isolated by the removal of a part of (he stand are so subject to 
windthrow that any method of reserving seed trees of these species 
or of making a selection cutting is technically undesirable. Steam 
logging, moreover, fits in well with the requirements of the species, 
except so far as it increases the fire hazard, for it helps to expose the 
mineral soil. 

SLASH DISPOSAL. 

Slash disposal in the heavy foi-ests of the Pacific coast regionj 
means the elimination of slash by broadcast burning. The objects 
are to reduce the fire hazard in the debris left after logging, to pro- 
vide a proper seed bed for reproduction, and to retard the spread of 
insect and fungous diseases. 

By far the most important of the above objects is to reduce the fire 
hazard. Since this is so the necessity for burning slash depends 
largely upon the fire menace of the region. Although in the spruce 
belt of Oregon and Washington the rainfall is abundant and fogs 
are frequent throughout most of the j'ear, there are two months or 
more in the summer when slashings become dry, and uncontrollable 
fires may start and do untold damage. Because of this Sitka spruce 
slashings in this region should ordinarily be burned. 



SITKA spruce: usks. growth, management. 31 

In Alaska, on the other hand, the danger of forest fires in the 
spruce belt is not great even in old cuttings because of frequent and 
heavy rains in the summer as well as throughout the rest of the year. 
Slash burning, therefore, is unnecessary and, moreover, highly un- 
desirable, because it destroys the layer of humus and duff with which. 
the rock is all too scantily covered in that thin-soiled country. For- 
esters recommend that in Alaska the slash be lopped and allowed to 
lie, and this is the required pi-actice after logging on the national 
forests of the Territory. 

If slash is to be burned in Sitka spruce stands, it is very important 
that it should be done the first spring or fall following logging, so 
that the crop of seedlings which springs up in the first growing sea- 
son after cutting will not be killed by the fire. Slash burning should 
also be done at a time when the weather conditions are such that 
the fire can be held in control on the area which it is intended to burn. 
Further, the slash fire should be hot enough to clean up all the 
inflammable debris. 

PROVISIONS FOR REPRODUCTION. 

Studies of old cuttings indicate that Sitka spruce reproduction 
ordinarily follows the removal of the virgin forest, unless the area 
has been subjected to repeated fires. Reproduction is abundant 
where the slash has not been burned at all, as well as where there 
has been but one slash fire immediately after logging. Sitka spriice 
seems to be represented in the reproduction in as abundant pro- 
portions as it was in the original forest. It is apparent that this 
abundant reproduction following logging comes fi'om seed which 
had accumulated in the ground before the virgin timber was cut, 
had escaped injury from fire (if the slashing was burned), and had 
germinated when the forest floor became exposed to the light and 
warmth of the sma's rays. Because of this adequate store of seed 
in the ground, special provisions for leaving spruce seed trees is not 
essential, provided only that the area is effectively safeguarded from 
fires after this seed genninates. As a precaution in case of an 
accidental fire, and as an added assurance of natural reproduction, 
it is well to leave occasional seed trees of sucii wind-firm associated 
species as Douglas fir, choosing those which are good seed producers. 
It is not ordinarily advisable to leave single seed trees of Sitka 
spruce, for they are too likely to be wind thrown. To secure some 
of this species in the next crop, reliance must be placed on the seed 
stored in the forest floor and released b}' the cutting of the virgin 
forest. 

If natural reproduction does not restock an area adequately, it 
may occasionally be advisable in the interest of good management 



32 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTTJKE. 

to renew the forest artificially by seeding or by planting mirsery- 
grown trees. This may be advisable if repeated fires have so de- 
nuded the land of seed trees and of reproduction arising from stored 
seed that there is no way for the natural regeneration of the stand 
to take place except by the slow process of migration from the sur- 
rounding timber. Methods of artificial reforestation of Sitka spruce 
are in general similar to those employed for Douglas fir. Occasion- 
ally successful results may be obtained from the direct sowing of 
seed on the denuded area, either broadcast or in sjDecially prepared 
spots. This method, however, is very uncertain because of the like- 
lihood of the seed being destroyed by birds or rodents and because 
of the heavy mortality which frequently occurs among the young 
seedlings during the first years after germination. Planting nursery- 
grown trees is a more dependable method, and while the initial 
expense may be greater than that of direct seeding, it may prove to 
be cheaper in the end. The use of 3-year-old transplant stock is 
recommended. On the better quality of sites Sitka spruce may be 
planted jDure over relatively small areas ; but, since it more commonly 
occurs associated with other species, a mixture of spruce with Douglas 
fir or hemlock is usually preferable. The composition of the former 
stand should largely govern the choice of species. 

ROTATION. 

A relatively short rotation is i^ossible in Sitka spruce forests be- 
cause of their rapid growth. Crops suitable for pulpwood might be 
produced on the best sites in 40 years or less, and crops for saw timber 
in twice that period. Information on the growth rate of the Alaskan 
forests is meager, but the indications are that a somewhat longer 
period will be required to j^roduce timber suitable for various pur- 
poses than is needed in Oregon and Washington. 



APPENDIX. 

Table 11. — Volume table fur Sitka spruce In Oregon and Waxliiiu/lun. 

This table is based on the iiieasui-fiiu'nr in 1914 and 1919 of 450 felled Sitka 
spruce (Picea sitehe7isis) trees, j,'rowu in fully stocked stands, averaged for all 
sites and seven localities at elevations from sea level to 1,200 feet, and from 
southern Oregon to northern Washington. Trees were scaled by Scribner 
Decimal C rule to a top diameter of 10 inches inside bark ; actual .height of stump 
was used (it averaged S feet) ; logs were scaled in 32-foot lengths and less, plus 
an allowance of 0.5 foot for trimming. The table was constructetl by the frustum 
form factor method and volumes curved. Trees are classified according to their 
diameter outside bark at 1 foot above pronounced basal swell, which was found 
to average 8 feet above ground. No allowance is made for defect or breakage. 
Breakage in 184 trees amounted to less than 2 per cent of merchantable volume. 





Aver- 
age.! 










Number of 32-foot logs. 














2 


2J 


I 


3i 


4 4i 5 1 51 


6 


»i 


7 


7i 


Ba.sis. 


eter 
above 


Total heigbt in feet. 


•well. 


112 


128 


142 


158 


173 1 188 1 202 1 217 


231 


241 










Volume In board feet In tens. 


Incites. 


5 

12 

19 

26 

40 

58 

83 

108 

140 

178 

219 

269 

317 

374 

431 

493 

558 

622 

692 

768 

842 

916 

998 

1,081 

1,169 

1,250 

1,334 

1,423 

1,514 

1,609 

1,862 

2,126 

2,412 

2,714 


26 
28 
30 
34 
39 
45 
51 
56 
























No. 
trea. 














... 
















41 
46 
63 
60 
69 
78 
88 
98 
110 
123 


























59 
69 
79 
90 
102 
115 
130 
144 
158 
174 
191 
208 
224 
239 
255 
























83 
96 
109 
123 
139 
158 
175 
195 
215 
237 
259 
283 
309 
335 
364 
395 


















»,J 




111 
129 
147 
167 

188 
210 
234 
258 
283 
310 
338 
369 
400 
433 
466 
503 
538 
















24 
















14 




172 
195 

220 
246 
273 
302 
330 
362 
394 
429 
464 
502 
542 
584 
626 
673 
718 
764 
811 
860 
911 


198 

226 
254 
283 
314 
346 
379 
415 
452 
491 
532 
576 
622 
668 
718 
769 
821 
875 
930 
987 
1,045 
1,107 
1,168 












24 


28 


255 

287 

321 

355 

382 

430 

469 

511 

554 

601 

650 

702 

755 

810 

868 

926 

988 

1,051 

1,115 

1,182 

1,252 

1,323 

1,509 

1,707 










2> 












37 


32 


358 

406 

437 

479 

523 

570 

619 

671 

726 

783 

842 

904 

968 

1,034 

1,102 

1,172 

1,246 

1,320 

1,397 

1,474 

1,680 

1,904 

2,148 

2,424 








Jl 


34 








24 


36 








10 


38 












25 


40 












31 














25 








686 

742 

802 

866 

932 

999 

1,069 

1,147 

1,220 

1,295 

1,373 

1,454 

1,639 

1,630 

1,862 

2,102 

2,374 

2,656 






13 


46 










26 


48 






881 
961 
1,022 
1,096 
1,173 
1,253 
1,334 
1,418 
1,605 
1,697 
1,690 
1,786 
2,037 
2.301 
2,586 
2,891 


1,278 
1,366 
1,455 
1,545 
1,638 
1,734 
1,833 
1,933 
2,199 
2,496 
2,814 
3,139 


20 


50 








19 


52 








18 








































60 




























64 














66 














68 














70 
















75 
















80 


















85 

















2 


90 






































450 



' \Then trees are not tallied by number of logs, use this column. 



33 



34 



BULLETIN 1060, V. S. DEPARTMENT OF AGRICULTURE. 



Table 12. — Volume iuMe for tlitka .spnice in Behtn Catuil (.Alaska) region. 

This table is based on taper measurements, in 1917, of 131 trees, total 
lieight and length of tip of 28 trees, and total height only of 92 trees which 
grew near Loring, Alaslca. Figures indicate merchantable volumes, scaled 
by Scribner Decimal C rule, and represent contents from stump height of 2 
feet and up to 6 inches d. i. b. at top. They are unreliable for trees over 44 
inches in diameter. The table was prepared under the direction of R. E. Kan 
Smith. 



Diameter breast-high. 


Volume. 


Diameter breast-high. 


Volume. 


Inches. 

24 


Boardfeet 
in tens. 
82 
101 
132 
154 
166 
192 
219 
260 
283 
318 
357 


Inches. 

46 


Boardfea 
in tent. 


26 


48 


445 


28. . . 


60 


491 


30 


52 




32 


64 


587 


34. 


56. . . 


639 


36 


58 




38 


60 


736 


40. . . . . 


62. .. . 


784 


m 


64 




41 


66 . . 


890 









Table 13. — Log volume table for Sitka spruce in Oregon and Washington. 

This table was constructed from measurements of 234 felled Sitka spruce 
trees in Oregon and Washington (the majority of which grew along the Hump- 
tulips River in Washington). By means of the Scribner Decimal C rule the 
volume of each log and its percentage of the total merchantable volume in the 
tree were calculated, and these percentages were curved and applied to the 
merchantable volume of the average tree for each diameter class. Logs are in 
32-foot lengths. 





Total 

mer- 
chant- 
able 
volume. 


Log volume and percentage of total volume. 




Diameter above 
. s. swell. 


Butt log. 


Second log. 


Third log. 


Fourth log. 


Basis. 


Inches. 
20 


Bd. ft. 
in tens. 
40 
58 
83 
108 
140 
178 

219 
269 
317 
374 
431 

493 

558 
622 
692 
768 

842 

916 

998 

' 1,081 

1,169 

1,250 
1,334 
1,423 
1,514 
1,609 

1,862 


Bd.ft. 

in tens. 
23 
32 
43 
53 
66 
79 

93 
109 
125 
143 
161 

181 
202 

222 
245 
269 

292 
315 
340 
365 
391 

413 

437 
461 
484 
510 

575 


Per 
•cent. 
57.8 
64.9 
52.2 
49.6 
47.1 
44.6 

42.6 
40.7 
39.4 
38.3 
37.5 

36.8 
37.3 
35.8 
35.4 
35.1 

34.7 
34.4 
34.1 
33.8 
33.5 

33.1 
32.8 
32.4 
32.0 
3L7 

30.9 


Bd.ft. 

in tens. 
13 
18 
28 
33 
42 
53 

64 
78 
91 
106 
122 

138 
156 
173 
192 
210 

229 
247 
268 
288 
309 

329 
348 
369 
392 
413 

472 


Per 
cent. 
33.7 


Bd.ft. 
in tens. 


Per 
cent. 


Bd.ft. 

in tens. 


Per 
cent. 


No. 
trees. 


22 


32.5 










9 


24.... 


31.6 
30.8 
30.3 
29.8 

29.4 
29.0 
28.7 
28.5 
28.3 

28.1 
28.0 
27.9 
27.7 
27.4 

27.2 
27.0 
26.9 
26.7 
26.5 

26.3 
26.1 
26.0 
25.9 
25.7 

25.4 










9 


26. 










10 


28 










8 


30. 


34 

42 
53 
62 
74 
86 

98 
112 
124 
139 
155 

171 
187 
204 
223 
242 

• 259 
277 
296 
316 
338 

395 


19.4 

19.5 
19.6 
19.7 
19.8 
19.9 

19.9 
20.0 
20.0 
20.1 
20.2 

20.3 
20.4 
20.5 
20.6 
20.7 

20.7 
20.8 
20.8 
20.9 
21.0 

2L2 






14 


32 






n 


34... 






23 


36 


35 
41 

47 

55 
63 
71 
80 
89 

98 
108 
119 
129 
141 

152 
164 
178 
191 
204 

244 


11.0 
ILO 
11.1 

11.2 
1L3 
11.4 
11.5 
11.6 

11.7 
11.8 
11.9 
12.0 
12.1 

12.2 
12.3 
12.5 
12.6 
12.7 

13.1 


38 


38 





40 


19 


S.... 





44 


32 


46 





48 


18 


50 





g 


15 


64 





56 - 


14 


58 





60 


4 


62 





64 


4 


66 





68 


5 


70 





75 . 


i 
234 



SITKA SPRUCE : USES, GROWTH, MANAGEMENT. 



35 



Table 14. — Voiiiparalire diameters at breast height and above swell of Sitka 

spruce, based on maximum taper. 

This table is based on maximum taper measurements of 37 trees which 

grew in Oregon and Washington. The figures under " taper " are inches per 

foot of vertical distance. The diameters above swell are noted for average 

lieights of swell. 

(Curved.) 



Diameter breast- 
high. 


Diameter 
above 
swell. 


Average 
height 
or swell. 


Taper. 


Dia 

110. 
115. 
120. 
125. 
130. 
135. 
140. 
145. 


meter breast- 
high. 


Diameter 
above 
swell. 


Average 
height 
of swell. 


Taper. 


Indies. 
«0 


Inches. 
51 

56 
61 
66 
67 
71 
76 
72 
77 
81 


Feet. 


Inches. 

1 3.5 

\ 3.5 

3.6 

\ 3.7 

3.8 

3.9 

. 4.0 

tl 
I 4.3 


Inches. 


Inches. 
76 
80 
85 
89 
93 
97 
102 
106 


Feet. 
I 12 

12 

} ^^ 


Inches. 
1 4.6 


65 




J 4.6 


70 




4.7 


75 




4.8 


80 




t 4.» 


85 




1 s.e 


90 




/ 't 


95 




\ 5.3 


100 






105... 









TABLE 15.' — Average total heiffht of Sitka spnice on all sites hi different parts 
of Oregon and Washington. 

(Curved.) 



Age. 


Tsiltcoos. 


Newport. 


Clatsop. 


Ray- 
mond. 


Hoquiam. 


Beaver. 


Average. 




Total height in feet. 


Years. 
20 


22 
44 
62 
82 
100 
118 
134 
148 
158 
163 
176 
184 
190 
196 
200 
205 


20 
34 
51 
70 
89 
108 
121 
134 
147 
157 
167 
175 
183 
190 
196 
201 
205 
210 
213 
216 
218 
220 
222 
224 


4S 
66 
.S2 
96 
109 
122 
133 
144 
155 

105 
173 
181 
188 
194 
199 
204 
208 
212 
215 
217 
220 
222 
223 
225 


32 
52 
70 
85 
98 
110 
120 
130 
139 
148 
156 
104 
171 
178 
184 
190 
196 
201 
206 
210 
214 
218 
■ 221 
223 


28 
48 
66 
83 
99 
114 
127 
141 
154 
166 
176 
ISO 
194 
201 
205 
213 
218 
223 
227 
230 
234 
236 
239 
241 


38 
60 
85 
110 
130 
147 
161 
173 
183 
192 
201 
209 
216 
222 

227 
232 
236 
240 
244 

246 
249 
251 
252 
254 


31 


,30 


51 




7e 


50 


87 


fiO 


104 


70. . 


119 


SO 


132 


90 


144 


100 


154 


110 


164 


120 


173 


130 


181 


140 


188 


150 


194 


160 


200 


170 


206 


180 


210 


190 




214 


200 




218 






221 


220 




224 






226 


240. .. 




228 


250 




230 



' The following is a description of the localities In which the growth measurements were talcen: 

Tsiltcoos Lake, Lane County, Oreg. — Pure stand of even-aged second growth (175 years) on gentle 
slopes, at elevation of 150 to 300 feet. Soil deep, loose, sandy to sandy loam; moist but well drained. 
; Newport, Lincoln County, Oreo.— Three types; 130-y6ar-old pure stand on moist, well-drained flat at 
200-foot elevation in deep sandy loam; 320-year-old stand mixed with young hemlock on slopes, 300 to 350 
feet above sea level in deep, well-drained sandy loam; and 300-year-old mixed stand in wet clay loam of creeli 
bottom, 25 to 50 feet in elevation. 

Clatsop, Clatsop County, Orcy.— Two types: SOB-year-old pure stand on gentle slopes at altitudes of 900 to 
1,100 feet, deep, moist, well-drained clay loam; 300-year-old stand in mixture with hemlock on level ground 
of wet clay loam at altitude of 400 feet. 

^Raymond, Pacific County, Wash.— Two types; small groups of even-age, varying between 110 and 440 
years", on slopes of moderate pitch, well drained, deep, and of clay loam; parklike stand on poorly drained 
bat. at elevation of 250 to 300 feet. 

JtHoquiam, Grays Harbor County, Wosft.— Two types; 2J0-year-old pure stand on moist, well-drained flat, 
at 400 feet elevation, in loamy soil underlain with gravel; 350-year-old stand in mixture on wet poorly 
drained flat, of clayey soil at same elevation. 

Beaver, Clallam County, Wash.— Three hundred-year-old, pure stand in very moist, level, creek basin of 
rich alluvial soil at altitude of 000 feet. 



3() BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. 

Table 15. — Atyerage total height of Sitka spruce, etc. — Continued. 



Age. 


Tsiltcoos. 


Newport. 


C'ats»p. ^n^'d. 


Hoquiam. 


Beaver. 


Average. 




Total height in feet. 


Kears— Conlinuod. 
2ii() 




225 
227 
228 


226 
227 
228 
229 
230 

231 
231 
231 
232 
232 

232 
232 
233 
233 
234 


225 
227 
229 
230 
231 

232 
232 
232 
233 
233 

233 
234 
234 
234 
234 


242 
243 
244 
245 
246 

246 
246 
247 
247 
247 

248 
248 
248 
249 
249 


255 
256 
258 
259 
260 


232 
233 
234 
235 
236 


271) 




2S0 




290 




300 




230 

230 
231 


310 




320 








330 




231 
231 
232 

232 
232 
232 






340 








:)o0 








360 








370 








.380 









390 








400 




















Basis: Number of measiire- 


220 


1S9 


220 


311 


138 


182 









Table 16.' — Average diameter outside bark at ir> feet above ground of Sittca 
spruce on all sites in different parts of Oregon and Washington. 

(Curved.) 



Age. 



Tsiltcoos. Newport. Clatsop. 



Ho- 
quiam. 



Beaver. 



Average. 



Diameter in inches outside bark at 15 feet. 



16.6 
19.7 

22.3 
24.6 



28.4 
30.1 
31.5 
32.8 
34.3 



For description of localities see footnote to Table 15. 



2.3 


3.2 


1.6 


2.2 


3.4 


6.3 


7.2 


4.4 


5.2 


8.3 


10.0 


11.1 


7.2 


8.3 


12.4 


13.7 


14.1 


9.7 


11.2 


16.2 


16.8 


16.5 


12.3 


13.7 


19.2 


19.7 


18.5 


14.7 


15.9 


21.7 


22.3 


20.4 


16.9 


18.1 


23.9 


24.6 


22.1 


19.1 


20.1 


25.8 


26.6 


24.8 


21.2 


22.0 


27. « 


28.6 


25.5 


23.3 


23.7 


29.5 


30.3 


27.2 


25.4 


25.4 


31.0 


31.8 


28.8 


27.6 


27.2 


32.6 


33.2 


30.3 


29.7 


28.8 


33.8 


34.8 


32.8 


31.8 


30.4 


35.2 


36.6 


33.3 


34.0 


32.0 


36.4 


37.7 


34.9 


36.1 


33.6 


37.8 


39.1 


36.4 


38.2 


35.1 


39.0 


40.3 


37.8 


40.3 


36.7 


40.2 


41.7 


39.3 


42.4 


38.2 


41.3 


43.0 


40.7 


44.6 


39.7 


42.2 


44.3 


41.9 


46. 7 


41.2 


43.3 


45.5 


43.1 


48.7 


42.7 


44.2 


46.7 


44.2 


50.5 


44.2 


45.2 


47.8 


45.3 


52.3 


45.7 


46.1 


48.8 


46.3 


54.0 


47.8 


47.1 


49.8 


47.3 


55.4 


48.7 


48.0 


50.8 


48.3 


56.8 


50.1 


48.9 


51.8 


49.3 


68.0 


51.6 


49.7 


52.8 


50.3 


59.3 


52.9 


50.6 



15.7 
18.2 
20.6 
22.5 
24.4 



34.7 
36.2 
37.7 
39.2 
40.6 

42.0 
43.4 
44.8 
46.2 
47. S 

48.8 
60.1 
51.4 
52.7 
54.0 



srTKA spruce: uses, growth, management. 



37 



Table 16. — Average diameter outside hark at 15 feet above ground of Sitka 
spruce on all sites in different parts of Oregon and Washington — Coutinued. 



Age. 


Tsiltcoos. 


Newport. 


1 


Hoquiam, 


Beaver. 


.\verage. 




i'f ars— Continued. 


Diameter in inches outside bark at 15 feet. 


310.. 






51.4 
52.4 
53.5 
54.5 


60.5 
61.7 
62.8 
64.0 
65.1 


54.4 
55.8 
57.2 
58.6 
fiO.O 




55.3 


320 . 




54.8 
55.7 
56.7 
57.5 




56.6 


330 . 






57.8 






59.0 


350 . 




fiO.'i 


360 




66.2 I 61.4 




61.4 










67.3 
68.4 
69.6 


62.8 






380 . 










63.6 














64.7 


400 












65.8 
















67.3 




Number trees 
















Basis 


95 1 78 


100 


133 73 


78 


557 



Table 17. — Results of tests on Sitka spruce wood from Washington, in green 
and air-dry condition, in the form of small clear pieces} 

[From Table 1, U. S. Dept. Agr. Bull. 556.) 



Mechanical property. 



Number of rings per inch 

Summerwood (per cent) 

Moisture content tper cent ) 

Specific gravity, based on volume and weight when oven-dry 

Weight per cubic foot (pounds) 

Shrinkage from green to oven.dry condition: 

Radial (per cent) '. 

Tangential (per cent) .* 

Static Lending: 

Fiber stress at elasticlimit (pounds per square inch) 

Modulus of rupture (pounds per square inch) 

Modulus of elasticity (1,000 pounds per square inch) 

Work to maximum load ' (inch poimds per cubic inch) 

Compression parallel to grain: 

Maximum crushing strength (pounds per square inch) 

Compression perpendicular to grain: 

Fiber stress at elastic limit (pounds per square inch) 

Shearing strength parallel to grain (pounds per square inch) 

Tension perpendicular to grain (pounds per square inch) 

Hardness, side: 

Load required to embed 0.444-iuch ball to one-half its diameter (pounds) 



Air-dry 
condi- 
tion. 



7, 2ai 

11,200 
1,610 
10.4 



' Test specimens were 2 inches by 2 inches in section. Bending specimens were cut .10 inches long; others 
were shorter, depending on test. 
2 Work to maximum load represents the shock-absorbing a'lility of the wood. 



LUMBER GRADES. 



The following lumber grades are in use for different Sitka spruce 
products : ^' 



Finish : B and Better. 
Flooring: B and Better. 
Ceiling: B and Better. 
Stepping: B and Better. 
Battens: B and Better. 



Partition : B and Better. 
Bevel siding: A, B, C. 
Wagon-box sets : B and Better. 
Boards and strips : Selected Common, 
No. 1 Common. 



"For further information, see West Coast Lumbei-man's Association, "Rule 2: Stand- 
ard Classiflcation, Grading, and Dressing Rules for Douglas Fir, Sitka Spruce, Cedar, 
and Western Hemlock Products,." Januai-y 22, 1922. 



38 



BULLETIN 1060, V. S. DEPARTMENT OP AGKICULTURE. 



Dimension, plank, and small timbers : 
Selected Common, Common. 

Lath : Standard Grade. 

Turning squares : Standard Grade. 

Molding stock : Standard Grade. 

Panel stock : No. 1, No. 2. 

Factory lumber : Select Factory, No. 1 
Shop, No. 2 Shop, 1-ineh Shop Com- 
mon. 



Car siding and roofing: B and Better. 

Ladder stock : Special Grade. 

Cut-up sash and door stock: No. 3, 

No. 2. 
Piano posts : Special Grade. 
Sounding-board stock : Special Grade. 
Box lumber : No. 1, No. 2, No. 3. 
Airplane stock : Special Grade. 
Flitches : Special Grade. 



LOG GRADES IN BRITISH COLUMBIA.' 



SPRUCE, PINE, AND COTTONWOOD. 



No. 1 : Logs 12 feet and over in length, 30 inches in diameter and over, up to 
32 feet long, 24 inches if over 32 feet long, reasonably straight, clear, free from 
such defects as would impair the value for clear lumber. 

No. 2 : Logs less than 14 inches in diameter and not over 24 feet long, or not 
less than 12 inches in diameter and over 24 feet long, sound, reasonably straight, 
free from rotten knots or bunch knots, and the grain straight enough to insure 
strength. 

No. 3 : Logs having visible defects, such as bad crooks, bad knots, or other 
defects that would lower the grade of lumber below merchantable. 

Cull : Logs lower in grade than No. 3 will be classed as culls. 

" " Forests of British Columbia," by H. N. Wbitford and R. D. Craig, p. 170, 1918. 



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